Keystones Cornerstone — Jul 16 - 22 | Maths Vault

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Cornerstone Jul 16 - 22 25 questions

Monday 13 July 2026

Keystones #28 · Five questions · Open this day only

1. Number

Calculate: 77 + 33

Answer: 77 + 33 = 110
2. Algebra

Solve: 2x = 18

Answer: x = 9
3. Geometry

Calculate the area of a circle with diameter 15cm

Answer: 176.71cm²
4. Ratio

Calculate 25% of 111

Answer: 27.75
5. Statistics

Find the range of: 19, 26, 12, 14, 31

Answer: 19

Tuesday 14 July 2026

Keystones #29 · Five questions · Open this day only

1. Number

Calculate: 45 + 71

Answer: 45 + 71 = 116
2. Algebra

What is the next term? 8, 32, 128, 512, ...

Answer: 2048
3. Geometry

Opposite = 11cm, adjacent = 16cm. Calculate the angle

Answer: 34.5°
4. Ratio

Simplify: 24:8:16

Answer: 3:1:2
5. Statistics

Calculate the mean of: 41, 19, 31, 17, 12, 22

Answer: 23.7

Wednesday 15 July 2026

Keystones #30 · Five questions · Open this day only

1. Number

What is the missing number: 68 + ? = 127

Answer: 59
2. Algebra

Expand: 8(x + 2)

Answer: 8x + 16
3. Geometry

Find the area of a circle with radius 5cm

Answer: 78.54cm²
4. Ratio

Simplify: 6:12:12

Answer: 1:2:2
5. Statistics

Find the range of: 17, 24, 14, 17, 19

Answer: 10

Thursday 16 July 2026

Keystones #31 · Five questions · Open this day only

1. Number

800000

Answer: 8 × 10⁵
2. Algebra

Solve: x + 10 = 20

Answer: x = 10
3. Geometry

Opposite = 18cm, adjacent = 13cm. Calculate the angle

Answer: 54.2°
4. Ratio

Simplify: 24:8:16

Answer: 3:1:2
5. Statistics

Find the mean of: 6, 18, 16, 17

Answer: 14.25

Friday 17 July 2026

Keystones #32 · Five questions · Open this day only

1. Number

What is the missing number: 56 + ? = 190

Answer: 134
2. Algebra

Solve: 5x = 25

Answer: x = 5
3. Geometry

Opposite = 6cm, hypotenuse = 8.5cm. Find the angle

Answer: 45° (approximately)
4. Ratio

Simplify: 4:10:4

Answer: 2:5:2
5. Statistics

A bag has 3 red and 3 blue balls. What is the probability of picking a red ball?

Answer: ¹⁄₂