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Prior-knowledge relay and maths bingo for CBSE Class 9 and 10

Find out what your new class remembers, without a test. ‘Find someone who…’ bingo gets everyone moving, then a team relay where each answer is needed for the next question checks the key skills from the last class.

Level
CBSE Class 9 and 10
Time
35 minutes, plus a 10-minute extension
Topics
Real numbers: HCF and LCM; Linear equations and polynomials; Lines and angles, area and statistics
Equipment
No calculator. Every answer works out exactly.

Download student sheet (PDF)Answers (PDF)

Suggested timings

PartTimeWhat
Starter5 minQuick questions on the board
Main: task A10 minLeg 1: numbers
Main: task B10 minLeg 2: algebra
Main: task C10 minLeg 3: shape and data
Extension10 minFast finishers or homework

Starter (5 minutes)

‘Find someone who can…’ bingo: a different classmate for each square.

  1. Find someone who can tell you the sum of the interior angles of a pentagon.
  2. Find someone who can expand (x + 3)(x − 5).
  3. Find someone who can work out 15% of 80.
  4. Find someone who can solve 3x + 7 = 22.

Main activity (30 minutes)

Task A: Leg 1: numbers (10 min)

Each answer is passed to the next person.

  1. Find the HCF of 36 and 48. Pass on your answer, A.
  2. Find the LCM of A and 18. Pass it on as B.
  3. Work out √B + B/4. Pass it on as C.
  4. Without dividing, say whether 1/C has a terminating decimal expansion, and why.

Task B: Leg 2: algebra (10 min)

Each answer is passed to the next person.

  1. Solve 2(x − 3) = 14. Pass on A = x.
  2. An AP starts A, A + 4, A + 8, … Find its 20th term. Pass it on as B.
  3. Find y when x = 2 on the line y = Bx − 100. Pass it on as C.
  4. Find the zeroes of p(x) = x2 − (C + 9).

Task C: Leg 3: shape and data (10 min)

Each answer is passed to the next person.

  1. Find the area of a triangle with base 12 cm and height 7 cm. Pass on A, the number of cm2.
  2. The mean of five numbers is A. Four of them are 40, 45, 38 and 50. Find the fifth. Pass it on as B.
  3. Two angles of a triangle are B° and (B + 13)°. Find the third angle. Pass it on as C.
  4. Find the exterior angle next to the interior angle of C°.

Extension (10 minutes)

For fast finishers.

  1. Solve the pair of linear equations 2x + y = 11 and x − y = 1.

For teachers

Teacher notes and full worked answers
  • ‘Find someone who…’ bingo (starter): students walk round with the sheet and find a different classmate who can do each one; that classmate writes the answer and their initials. First to fill the sheet with correct answers wins. It mixes the class and shows you, at a glance, what was remembered from last year.
  • Relay: teams of four sit in a row. Student 1 answers question (a) and passes the answer to student 2, who needs it for (b), and so on. The team brings you the final answer; if it is wrong, they find the broken link together. Nothing is recorded on the site.
  • Afterwards, set the baseline test for a fuller picture of what each student remembers; 20 multiple-choice questions with an instant topic-by-topic report.

Starter

  1. 540°
    • (5 − 2) × 180 = 540
  2. x2 − 2x − 15
    • x2 − 5x + 3x − 15
  3. 12
    • 10% = 8 and 5% = 4
  4. x = 5
    • 3x = 15

Task A: Leg 1: numbers

  1. 12
    • 36 = 22 × 32, 48 = 24 × 3
    • HCF = 22 × 3 = 12
  2. 36
    • 12 = 22 × 3, 18 = 2 × 32
    • LCM = 22 × 32 = 36
  3. 15
    • 6 + 9 = 15
  4. No: it does not terminate
    • 15 = 3 × 5. The denominator has a prime factor other than 2 and 5, so 1/15 = 0.0666… repeats.

Task B: Leg 2: algebra

  1. 10
    • x − 3 = 7
  2. 86
    • a20 = 10 + 19 × 4 = 86
  3. 72
    • 86 × 2 − 100 = 72
  4. 9 and −9
    • x2 − 81 = (x − 9)(x + 9)

Task C: Leg 3: shape and data

  1. 42
    • ½ × 12 × 7 = 42
  2. 37
    • 5 × 42 = 210
    • 210 − 173 = 37
  3. 93
    • 180 − 37 − 50 = 93
  4. 87°
    • 180 − 93 = 87

Extension

  1. x = 4, y = 3
    • Add: 3x = 12
    • y = 4 − 1 = 3

The same answers are in the answers PDF. Every answer was recomputed by computer before publishing.

Practise the topics

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