Infographic showing CBSE Class 10 Maths chapter-wise important questions covering Real Numbers, Polynomials, Trigonometry and other chapters for 2026 board exam preparation.

Table of Contents

Introduction

Welcome to your ultimate board exam preparation guide for CBSE Class 10 Maths! Mathematics is a scoring subject, but it requires a strategic approach. Instead of practising every single question, focusing on high-priority patterns, competency-based questions, and core concepts can save you time and boost your score. This chapter-wise resource is designed strictly as per the latest CBSE syllabus and exam pattern.

Chapter 1: Real Numbers

Important Topics

  • Euclid’s Division Algorithm
  • Fundamental Theorem of Arithmetic
  • Finding HCF and LCM using prime factorization
  • Proving the irrationality of numbers
  • Terminating and non-terminating decimal expansions

Important Formulas & Concepts

  • \( HCF(a, b) \times LCM(a, b) = a \times b \)
  • A rational number has a terminating decimal expansion if the denominator’s prime factorization is of the form \( 2^n \times 5^m \) (where n, m are non-negative integers).

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1The decimal expansion of the rational number \( 17/8 \) will terminate after how many places?MCQEasy8 is \( 2^3 \). The denominator is of the form \( 2^n \). Therefore, it terminates after 3 decimal places.
2Prove that \( 3 + 2\sqrt{5} \) is an irrational number.SAMediumAssume it is rational \( p/q \). Rearranging gives \( \sqrt{5} = (p – 3q) / 2q \), implying \( \sqrt{5} \) is rational, which is a contradiction. Hence proved.
3Three bells toll at intervals of 9, 12, and 15 minutes. If they start tolling together, after what time will they next toll together?Competency-BasedMediumFind LCM of 9, 12, 15. LCM = \( 2^2 \times 3^2 \times 5 = 180 \) minutes = 3 hours.
4Show that any positive odd integer is of the form \( 6q + 1 \), \( 6q + 3 \), or \( 6q + 5 \).LAHardBy Euclid’s algorithm, \( a = 6q + r \) where \( 0 \leq r < 6 \). Since \( a \) is odd, \( r \) cannot be 0, 2, or 4. Thus, \( r \) is 1, 3, or 5.

Most Important Questions

  1. Prove that \( \sqrt{5} \) or \( 3 + 2\sqrt{5} \) is irrational.
  2. Word problems based on finding LCM and HCF (e.g., bell tolling, distributing items equally).
  3. Finding the nature of decimal expansion based on denominator properties.

Exam Tips

  • Always state your assumption clearly for irrationality proofs: “Let us assume… is rational.”
  • In decimal expansion questions, always factorize the denominator to its lowest prime factors first.

Chapter 2: Polynomials

Important Topics

  • Zeros of a polynomial and their geometric meaning
  • Relationship between zeros and coefficients
  • Division algorithm for polynomials

Important Formulas & Concepts

  • For a quadratic polynomial \( ax^2 + bx + c \):
    Sum of zeros \( (\alpha + \beta) = -b/a \)
    Product of zeros \( (\alpha \times \beta) = c/a \)
  • Division Algorithm: \( p(x) = g(x) \times q(x) + r(x) \), where Degree of \( r(x) < \) Degree of \( g(x) \).

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1If \( \alpha \) and \( \beta \) are zeros of \( x^2 – 5x + 6 \), find \( \alpha + \beta \).MCQEasyHere \( a=1, b=-5 \). Sum = \( -b/a = 5 \).
2Find the zeros of \( x^2 – 2x – 8 \) and verify the relationship to coefficients.SAMedium\( x^2 – 4x + 2x – 8 = 0 \) \( \Rightarrow \) \( x(x-4)+2(x-4)=0 \). Zeros are 4, -2. Sum = 2 (-b/a). Product = -8 (c/a).
3If the polynomial \( x^4 – 6x^3 + 16x^2 – 25x + 10 \) is divided by \( x^2 – 2x + k \), the remainder is \( x + a \). Find k and a.HOTSHardBy division, remainder is \( (2k-9)x + (10-8k+k^2) \). Equating: \( 2k-9 = 1 \) \( \Rightarrow \) \( k=5 \). \( 10-40+25 = a \) \( \Rightarrow \) \( a=-5 \).

Chapter 3: Pair of Linear Equations in Two Variables

Important Topics

  • Graphical solution of linear equations
  • Substitution and Elimination methods
  • Conditions for consistency (unique, infinite, no solution)

Important Formulas & Concepts

  • Consistent (unique): \( a_1/a_2 \neq b_1/b_2 \)
  • Inconsistent (no solution): \( a_1/a_2 = b_1/b_2 \neq c_1/c_2 \)
  • Infinitely many solutions: \( a_1/a_2 = b_1/b_2 = c_1/c_2 \)

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1For what value of k does \( 2x+3y=5 \) and \( 4x+ky=10 \) have infinitely many solutions?MCQEasy\( 2/4 = 3/k \Rightarrow 1/2 = 3/k \Rightarrow k = 6 \).
2Solve \( 2x+3y=11 \) and \( 2x-4y=-24 \). Find m for which \( y=mx+3 \).SAMediumSubtracting equations gives \( 7y=35 \Rightarrow y=5 \). Then \( x=-2 \). Substitute in \( y=mx+3 \): \( 5 = m(-2)+3 \Rightarrow m=-1 \).
3A fraction becomes 1/3 when 1 is subtracted from the numerator, and 1/4 when 8 is added to the denominator. Find the fraction.Case-BasedHardLet fraction be \( x/y \). \( 3x-y=3 \) and \( 4x-y=8 \). Solving gives \( x=5, y=12 \). Fraction is 5/12.

Most Important Questions

  1. Finding the value of ‘k’ for a specific type of consistency.
  2. Word problems forming linear equations (fractions, ages, two-digit numbers).

Exam Tips

  • In graphical questions, plot points neatly. Always write the scale used on the x and y axes and mark coordinates clearly next to points.

Chapter 4: Quadratic Equations

Important Topics

  • Solving by factorization and quadratic formula
  • Nature of roots (Discriminant)
  • Word problems forming quadratic equations

Important Formulas & Concepts

  • Discriminant \( D = b^2 – 4ac \)
  • Roots = \( (-b \pm \sqrt{D}) / (2a) \)
  • D > 0: Two distinct real roots; D = 0: Two equal real roots; D < 0: No real roots.

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1Find the nature of roots for \( 2x^2 – 4x + 3 = 0 \).VSAEasy\( D = (-4)^2 – 4(2)(3) = 16 – 24 = -8 \). Since D < 0, no real roots.
2Find the roots of \( 2x^2 – 7x + 3 = 0 \) using the quadratic formula.SAMedium\( D = 49 – 24 = 25 \). Roots = \( (7 \pm 5) / 4 \). Roots are 3 and 1/2.
3A train travels 360 km at a uniform speed. If speed had been 5 km/h more, it would have taken 1 hour less. Find the speed.LAHardLet speed be x. \( 360/x – 360/(x+5) = 1 \). Gives \( x^2+5x-1800=0 \). Solving gives x=40 km/h (rejecting negative).

Most Important Questions

  1. Word problems based on speed/distance/time and age.
  2. Questions asking to find the value of ‘k’ for which roots are equal (D=0).

Exam Tips

  • For word problems, always write a concluding sentence with proper units. Reject inadmissible roots (like negative speed or age) with an explicit reason.

Chapter 5: Arithmetic Progressions (AP)

Important Topics

  • Finding the nth term of an AP
  • Sum of first n terms
  • Real-life application problems

Important Formulas & Concepts

  • nth term: \( a_n = a + (n – 1)d \)
  • Sum of n terms: \( S_n = (n / 2) \times [2a + (n – 1)d] \) OR \( S_n = (n / 2) \times [a + l] \)

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1Find the 10th term of the AP: 5, 8, 11, 14…MCQEasy\( a=5, d=3 \). \( a_{10} = 5 + 9 \times 3 = 32 \).
2If the sum of first 14 terms is 1050 and first term is 10, find the 20th term.SAMedium\( S_{14} = 7[20 + 13d] = 1050 \) \( \Rightarrow \) \( 20+13d = 150 \) \( \Rightarrow \) \( d=10 \). \( a_{20} = 10 + 19 \times 10 = 200 \).
3Ratio of sums of first m and n terms is \( m^2 : n^2 \). Show ratio of mth and nth terms is \( (2m-1) : (2n-1) \).HOTSHardProve by taking \( S_m / S_n = m^2 / n^2 \). Simplify to find \( d = 2a \). Substitute \( d=2a \) in \( a_m / a_n \) to get the result.

Chapter 6: Triangles

Important Topics

  • Similarity of triangles (AA, SSS, SAS criteria)
  • Basic Proportionality Theorem (BPT / Thales’ Theorem)
  • Ratio of areas of similar triangles
  • Pythagoras Theorem and its converse

Important Formulas & Concepts

  • Ratio of areas of similar triangles = Ratio of squares of corresponding sides: \( (AB/DE)^2 \)
  • BPT: If a line is parallel to one side of a triangle, it divides the other two sides proportionally.

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1If \( \triangle ABC \sim \triangle PQR \), \( AB=4 \), \( PQ=6 \), area of \( \triangle ABC = 16 \), find area of \( \triangle PQR \).MCQEasy\( 16 / \text{Area}(PQR) = (4/6)^2 = 16/36 \). Area = 36 sq cm.
2State and prove the Basic Proportionality Theorem.LAMediumStandard NCERT proof using area of triangles and congruency rules.
3In an equilateral triangle ABC, D is on BC such that \( BD = (1/3)BC \). Prove \( 9 \times AD^2 = 7 \times AB^2 \).HOTSHardDraw altitude AE. Let side be x. \( BD = x/3 \), \( DE = x/6 \). In \( \triangle AED \), \( AD^2 = AE^2 + DE^2 = (3x^2/4) + (x^2/36) = 28x^2/36 = 7x^2/9 \). Thus, \( 9AD^2 = 7AB^2 \).

Most Important Questions

  1. Proof of BPT.
  2. Questions involving ratios of areas and Pythagoras application in triangles.

Exam Tips

  • Always write the similarity criterion explicitly (e.g., “By AA similarity criterion…”) and maintain correct vertex correspondence.

Chapter 7: Coordinate Geometry

Important Topics

  • Distance formula
  • Section formula (internal division and midpoint)
  • Area of a triangle formed by three points

Important Formulas & Concepts

  • Distance: \( \sqrt{(x_2 – x_1)^2 + (y_2 – y_1)^2} \)
  • Section Formula: \( ((m \times x_2 + n \times x_1) / (m + n), (m \times y_2 + n \times y_1) / (m + n)) \)
  • Area of Triangle: \( (1/2) \times |x_1(y_2 – y_3) + x_2(y_3 – y_1) + x_3(y_1 – y_2)| \)

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1Find the midpoint of \( (x_1, y_1) \) and \( (x_2, y_2) \).MCQEasy\( ((x_1 + x_2) / 2, (y_1 + y_2) / 2) \).
2Find a relation between x and y such that point (x, y) is equidistant from (3, 6) and (-3, 4).SAMediumEquate distances squared: \( (x-3)^2 + (y-6)^2 = (x+3)^2 + (y-4)^2 \). Simplifies to \( 3x + y – 5 = 0 \).
3Vertices of quadrilateral ABCD are A(1,2), B(4,5), C(3,8), D(-1,6). Find its area.LAHardSplit into triangles ABC and ACD using area formula. Area ABC = 6, Area ACD = 10. Total = 16 sq units.

Most Important Questions

  1. Finding unknown coordinates when points form specific shapes (rhombus, parallelogram).
  2. Calculating the area of a triangle/quadrilateral and checking collinearity.

Exam Tips

  • To prove three points are collinear, calculate the area of the triangle formed by them. If the area is 0, they are collinear.

Chapter 8: Introduction to Trigonometry

Important Topics

  • Trigonometric ratios
  • Complementary angles
  • Trigonometric identities

Important Formulas & Concepts

  • \( \sin^2 \theta + \cos^2 \theta = 1 \)
  • \( 1 + \tan^2 \theta = \sec^2 \theta \)
  • \( 1 + \cot^2 \theta = \csc^2 \theta \)
  • \( \sin(90^\circ – \theta) = \cos \theta \), \( \tan(90^\circ – \theta) = \cot \theta \)

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1Evaluate \( \sin 30^\circ \times \cos 60^\circ + \cos 30^\circ \times \sin 60^\circ \).MCQEasy\( (1/2)(1/2) + (\sqrt{3}/2)(\sqrt{3}/2) = 1/4 + 3/4 = 1 \).
2Evaluate \( 2 \times \tan^2 45^\circ + \cos^2 30^\circ – \sin^2 60^\circ \).SAMedium\( 2(1)^2 + (\sqrt{3}/2)^2 – (\sqrt{3}/2)^2 = 2 + 3/4 – 3/4 = 2 \).
3Prove \( (\sin A – \cos A + 1) / (\sin A + \cos A – 1) = 1 / (\sec A – \tan A) \).LAHardDivide LHS num and den by \( \cos A \), then multiply num and den by \( (\sin A + \cos A + 1) \). Simplify using \( \sin^2 A + \cos^2 A = 1 \) to get \( \sec A + \tan A \). RHS rationalized gives the same.

Most Important Questions

  1. Proving trigonometric identities using the three fundamental identities.
  2. Evaluating expressions using complementary angles.

Exam Tips

  • When proving identities, start from the side that looks more complex. If stuck, convert all ratios to sin and cos.

Chapter 9: Some Applications of Trigonometry

Important Topics

  • Angle of elevation
  • Angle of depression
  • Right triangle word problems (Heights and Distances)

Important Formulas & Concepts

  • \( \tan \theta = \text{Perpendicular} / \text{Base} \)
  • \( \sin \theta = \text{Perpendicular} / \text{Hypotenuse} \)

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1If a tower’s height is \( \sqrt{3} \) times its shadow, the angle of elevation of the sun is:MCQEasy\( \tan \theta = \sqrt{3}/1 \Rightarrow \theta = 60^\circ \).
2A kite is flying at 60 m. The string inclination with ground is 60°. Find string length.SAMedium\( \sin 60^\circ = 60 / L \Rightarrow \sqrt{3}/2 = 60 / L \Rightarrow L = 120 / \sqrt{3} = 40\sqrt{3} \) m.
3From a 7 m high building, the angle of elevation of a tower’s top is 60°, and depression of its foot is 45°. Find tower height.LAHardDistance x = 7 m (since \( \tan 45^\circ = 7/x \)). Height above building \( h = x \tan 60^\circ = 7\sqrt{3} \). Total height = \( 7 + 7\sqrt{3} = 7(1+\sqrt{3}) \) m.

Most Important Questions

  1. Two-object problems involving both angle of elevation and angle of depression.

Exam Tips

  • Always draw a neat, labeled diagram. Mark the line of sight clearly and ensure all units are consistent.

Chapter 10: Circles

Important Topics

  • Tangent to a circle
  • Properties of tangents
  • Number of tangents from a point

Important Formulas & Concepts

  • The tangent at any point of a circle is perpendicular to the radius at the point of contact.
  • The lengths of tangents drawn from an external point to a circle are equal.

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1A tangent PQ at P of a circle of radius 5 cm meets a line through center O at Q. If OQ = 12 cm, find PQ.MCQEasy\( PQ = \sqrt{12^2 – 5^2} = \sqrt{144 – 25} = \sqrt{119} \) cm.
2Prove that lengths of tangents drawn from an external point to a circle are equal.LAMediumStandard proof using RHS congruency (\( \triangle OAP \cong \triangle OBP \)) where OA=OB (radii) and OP is common.
3Two concentric circles have radii 5 cm and 3 cm. Find the length of the chord of the larger circle that touches the smaller one.HOTSHardPerpendicular from center to chord bisects it. Half-chord = \( \sqrt{5^2 – 3^2} = 4 \) cm. Full chord = 8 cm.

Most Important Questions

  1. The proof of equal tangent lengths.
  2. Application questions combining Pythagoras theorem with tangent properties.

Exam Tips

  • Immediately apply Pythagoras theorem when you see a radius meeting a tangent at the point of contact.

Chapter 11: Areas Related to Circles

Important Topics

  • Area of a sector of a circle
  • Area of a segment of a circle
  • Combining circles with other shapes

Important Formulas & Concepts

  • Area of sector = \( (\theta / 360) \times \pi r^2 \)
  • Length of arc = \( (\theta / 360) \times 2 \pi r \)
  • Area of segment = Area of sector – Area of corresponding triangle

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1Find the area of a circle whose circumference is 22 cm.MCQEasy\( r = 22 / (2\pi) = 3.5 \) cm. Area = \( \pi r^2 = (22/7) \times 3.5 \times 3.5 = 38.5 \) sq cm.
2Find the area of a sector with radius 6 cm and angle 60°.SAMedium\( (60/360) \times (22/7) \times 36 = (1/6) \times (22/7) \times 36 = 132/7 \) sq cm.
3A chord of a circle of radius 15 cm subtends 60° at center. Find the area of the minor segment.LAHardSector area = 37.5 \pi. Triangle is equilateral, area = \( (225\sqrt{3})/4 \). Segment area = \( 37.5 \pi – (225\sqrt{3})/4 \).

Most Important Questions

  1. Finding the area of segments for 60°, 90°, and 120° angles.
  2. Finding areas of combined figures.

Exam Tips

  • Leave \( \pi \) in the final answer unless asked to evaluate. Always write correct units (sq cm, sq m).

Chapter 12: Surface Areas and Volumes

Important Topics

  • Combinations of solids (cylinder, cone, sphere, hemisphere)
  • Conversion of solids from one shape to another
  • Frustum of a cone

Important Formulas & Concepts

  • Volume of cylinder = \( \pi r^2 h \); Cone = \( (1/3) \pi r^2 h \); Sphere = \( (4/3) \pi r^3 \)
  • Volume of frustum = \( (1/3) \pi h (R^2 + r^2 + R \times r) \)

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1Two solid hemispheres of same base radius r are joined together. Volume of new solid?MCQEasyForms a sphere. Volume = \( (4/3) \pi r^3 \).
2A metallic sphere of radius 4.2 cm is melted into a cylinder of radius 6 cm. Find its height.SAMediumVolumes are equal. \( (4/3) \pi (4.2)^3 = \pi (6)^2 h \). \( h = 2.744 \) cm.
3A glass is a frustum of a cone of height 14 cm. Diameters of ends are 4 cm and 2 cm. Find capacity.LAHard\( R=2, r=1, h=14 \). Volume = \( (1/3) \times (22/7) \times 14 \times (4 + 1 + 2) = (44/3) \times 7 = 308/3 = 102.67 \) cubic cm.

Most Important Questions

  1. Melting and recasting problems (volume conservation principle).
  2. Calculating volume and surface area of a frustum.

Exam Tips

  • When a solid is melted and recast, always equate Volumes, never Surface Areas.

Chapter 13: Statistics

Important Topics

  • Mean of grouped data (Step-deviation method)
  • Mode of grouped data
  • Median of grouped data
  • Finding missing frequencies

Important Formulas & Concepts

  • Mean = \( A + h \times (\Sigma f_i u_i / \Sigma f_i) \), where \( u_i = (x_i – A) / h \)
  • Mode = \( l + [ (f_1 – f_0) / (2f_1 – f_0 – f_2) ] \times h \)
  • Median = \( l + [ (n/2 – cf) / f ] \times h \)

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1In the median formula, what does ‘l’ represent?MCQEasyLower limit of the median class.
2Find the mode of ungrouped data: 5, 7, 8, 7, 6, 5, 7, 9, 7, 8.SAMediumMost frequent observation = 7.
3Find the median for the frequency distribution: Classes 65-85…185-205 with frequencies 4, 5, 13, 20, 14, 8, 4.LAHardN=68, N/2=34. Median class = 125-145. \( l=125, cf=22, f=20, h=20 \). Median = \( 125 + [(34-22)/20] \times 20 = 137 \).

Most Important Questions

  1. Calculating Median and Mean.
  2. Finding missing frequencies when Mean or Median is given.

Exam Tips

  • Double-check your Cumulative Frequency (cf) column. A single addition error will ruin the entire calculation.

Chapter 14: Probability

Important Topics

  • Classical definition of probability
  • Sample space and events
  • Probability of dice, coins, and playing cards

Important Formulas & Concepts

  • \( P(E) = \text{Number of favorable outcomes} / \text{Total number of outcomes} \)
  • \( P(E) + P(\text{not } E) = 1 \)

Important Questions

No.QuestionTypeDifficultyAnswer/Solution
1The probability of an impossible event is:MCQEasy0
2One card is drawn from a deck of 52. Find the probability of a red face card.SAMediumRed face cards = 6. \( P = 6/52 = 3/26 \).
3A coin is tossed 3 times. Hanif wins if all outcomes are the same. Find P(Hanif losing).Case-BasedHardSample space = 8. Winning = {HHH, TTT} (2). Losing = 8-2 = 6. \( P = 6/8 = 3/4 \).

Most Important Questions

  1. Drawing balls from a bag.
  2. Playing card and double dice problems.

Exam Tips

  • Always write out the full sample space for coin/dice questions. For cards, list the composition (e.g., 26 red, 12 face cards) before calculating.

Common Mistakes to Avoid

  1. Sign Errors in Formulas: In Polynomials, students often write \( -b/a \) as \( b/a \) or vice versa. Always identify \( a, b, \) and \( c \) explicitly before substituting.
  2. Graph Plotting: In Linear Equations, using a blunt pencil or not writing coordinates next to plotted points can lead to marks deduction for presentation.
  3. Forgetting Units: In Mensuration (Surface Areas and Volumes) and Areas Related to Circles, leaving the final answer without units (like sq cm or cubic m) costs an easy half-mark.
  4. Cumulative Frequency Errors: In Statistics, one wrong addition in the cumulative frequency (cf) column shifts the median class entirely. Double-check this column.
  5. Inadmissible Roots: In Quadratic word problems, forgetting to reject negative or fraction values for physical quantities like speed, age, or time.

Final Revision Strategy

Step 1: Concept Revision

Skim through your NCERT textbook and notes. Focus on why a formula works and the proofs (BPT, Tangents, Trig identities). Do not try to learn new concepts at the last minute.

Step 2: Formula Revision

Create a cheat sheet with all formulas (especially Trigonometry, Mensuration, Coordinate Geometry, and Statistics). Read this sheet every morning and before sleeping.

Step 3: Important Question Practice

Solve the “Most Important Questions” listed in this guide. Time yourself strictly: 2 minutes for MCQs, 5-7 minutes for SA, and 10-12 minutes for LA.

Step 4: Case-Based & Competency Questions

Practice 2-3 Case-Based questions daily from Algebra and Geometry to get comfortable with interpreting paragraph-based data.

Step 5: Sample Paper Practice

Solve at least 3 official CBSE Sample Papers and 1 Previous Year Paper strictly in a 3-hour window. Train your brain for exam stamina.

Step 6: Mistake Analysis

Maintain an “Error Book”. Note down every calculation mistake or wrong formula used. Reviewing this book two days before the exam can save 10-15 marks.

Step 7: Final Revision

Put away all heavy books. Revise from your Formula Cheat Sheet and Error Book. Ensure your geometry box is fully stocked with a sharp pencil, good eraser, and clear ruler. Stay calm and confident.

FAQs

Q1. Which chapters are most important for CBSE Class 10 Maths?

Algebra (Quadratic Equations, Arithmetic Progressions), Geometry (Triangles, Circles), and Trigonometry carry high weightage. However, maximum marks can be secured easily from Statistics, Probability, and Mensuration.

Q2. How should I prepare important Maths questions?

Focus on understanding the underlying concept rather than rote memorizing the solution. Practice previous year questions and identify recurring patterns. Always write down formulas before solving.

Q3. How many questions should I practise before the board exam?

Quality over quantity. Practising 5-10 high-yield questions per chapter (as outlined in this guide) is better than blindly solving 50 repetitive questions. Ensure you solve at least 3 full-length sample papers.

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