Change pack
Lintel Jan 19 - 25 25 questions
PDF (questions) PDF (answers)

Monday 19 January 2026

Keystones #19 · Five questions · Open this day only

  1. 1. Number

    Express 200 as a product of prime factors

    Answer: 2³ × 5²
  2. 2. Algebra

    Solve: 2x + 3y = 41 and 3x - y = 23

    Answer: x = 10, y = 7
  3. 3. Geometry

    Find b if a = 13cm and c = 25cm

    Answer: 21.35cm
  4. 4. Ratio

    a:b is 1:2 and b:c is 4:7. Find a:b:c.

    Answer: 2:4:7
  5. 5. Statistics

    A bag has 4 red out of 8 balls. If you pick 74 times (with replacement), how many times would you expect red?

    Answer: 37

Tuesday 20 January 2026

Keystones #20 · Five questions · Open this day only

  1. 1. Number

    Write 90 as a product of its prime factors

    Answer: 2 × 3² × 5
  2. 2. Algebra

    Solve: 2x + 3y = 22 and 3x - y = 11

    Answer: x = 5, y = 4
  3. 3. Geometry

    Calculate the missing side: a = 24cm, c = 32cm

    Answer: 21.2cm
  4. 4. Ratio

    a:b is 3:5 and b:c is 5:6. Find a:b:c.

    Answer: 3:5:6
  5. 5. Statistics

    A fair coin is flipped 164 times. How many heads would you expect?

    Answer: 82

Wednesday 21 January 2026

Keystones #21 · Five questions · Open this day only

  1. 1. Number

    Express 144 as a product of prime factors

    Answer: 2⁴ × 3²
  2. 2. Algebra

    Solve: 5x + 3y = 37 and x + 3y = 17

    Answer: x = 5, y = 4
  3. 3. Geometry

    Find b if a = 13cm and c = 21cm

    Answer: 16.49cm
  4. 4. Ratio

    a:b is 4:5 and b:c is 5:4. Find a:b:c.

    Answer: 4:5:4
  5. 5. Statistics

    A bag has 3 red out of 10 balls. If you pick 116 times (with replacement), how many times would you expect red?

    Answer: 34.8

Thursday 22 January 2026

Keystones #22 · Five questions · Open this day only

  1. 1. Number

    Write 60 as a product of its prime factors

    Answer: 2² × 3 × 5
  2. 2. Algebra

    Solve: 2x + 2y = 32 and x + 4y = 40

    Answer: x = 8, y = 8
  3. 3. Geometry

    Calculate the missing side: a = 11cm, c = 22cm

    Answer: 19.cm
  4. 4. Ratio

    a:b is 2:5 and b:c is 5:4. Find a:b:c.

    Answer: 2:5:4
  5. 5. Statistics

    A bag has 2 red out of 10 balls. If you pick 54 times (with replacement), how many times would you expect red?

    Answer: 10.8

Friday 23 January 2026

Keystones #23 · Five questions · Open this day only

  1. 1. Number

    Express 100 as a product of prime factors

    Answer: 2² × 5²
  2. 2. Algebra

    Solve: 2x + 3y = 18 and 3x - y = 16

    Answer: x = 6, y = 2
  3. 3. Geometry

    Find b if a = 8cm and c = 18cm

    Answer: 16.12cm
  4. 4. Ratio

    a:b is 3:5 and b:c is 5:7. Find a:b:c.

    Answer: 3:5:7
  5. 5. Statistics

    A fair coin is flipped 58 times. How many heads would you expect?

    Answer: 29