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Number Foundations

16 practice questions with full worked solutions. Free, no account needed.

Problems & worked solutions

Problem #0844 UK GCSE

Problem 1Fractions, Decimals & Percentages

Write 34\dfrac{3}{4} as a percentage.

Show answer & worked solution
  1. A. 0.75%0.75\%
  2. B. 34%34\%
  3. C. 75%75\%✓ correct
  4. D. 43%43\%

34×100%=75%\dfrac{3}{4} \times 100\% = 75\%.

Problem #0845 UK GCSE

Problem 2Fractions, Decimals & Percentages

Write 0.20.2 as a fraction in its simplest form.

Show answer & worked solution
  1. A. 2100\dfrac{2}{100}
  2. B. 15\dfrac{1}{5}✓ correct
  3. C. 120\dfrac{1}{20}
  4. D. 25\dfrac{2}{5}

0.2=210=150.2 = \dfrac{2}{10} = \dfrac{1}{5}.

Problem #0846 UK GCSE

Problem 3Fractions, Decimals & Percentages

Find 15%15\% of 8080.

Show answer & worked solution
  1. A. 1212✓ correct
  2. B. 1515
  3. C. 1.21.2
  4. D. 2020

0.15×80=120.15 \times 80 = 12.

Problem #0847 UK GCSE

Problem 4Fractions, Decimals & Percentages

Which of these is the largest: 35\dfrac{3}{5},  0.55\ 0.55,  58%\ 58\%?

Show answer & worked solution
  1. A. 0.550.55
  2. B. 58%58\%
  3. C. 35\dfrac{3}{5}✓ correct
  4. D. They are all equal

35=0.6\dfrac{3}{5} = 0.6 and 58%=0.5858\% = 0.58.

Since 0.6>0.58>0.550.6 > 0.58 > 0.55, the largest is 35\dfrac{3}{5}.

Problem #0848 UK GCSE

Problem 5Integers, Primes, HCF & LCM

What is the highest common factor (HCF) of 2424 and 3636?

Show answer & worked solution
  1. A. 66
  2. B. 44
  3. C. 1212✓ correct
  4. D. 7272

24=23324 = 2^3 \cdot 3 and 36=223236 = 2^2 \cdot 3^2.

Shared primes at their lowest powers: 222^2 and 33.

HCF=43=12\text{HCF} = 4 \cdot 3 = 12.

Problem #0849 UK GCSE

Problem 6Integers, Primes, HCF & LCM

What is the lowest common multiple (LCM) of 66 and 88?

Show answer & worked solution
  1. A. 22
  2. B. 2424✓ correct
  3. C. 4848
  4. D. 1414

6=236 = 2 \cdot 3 and 8=238 = 2^3.

Highest powers: 232^3 and 33.

LCM=83=24\text{LCM} = 8 \cdot 3 = 24.

Problem #0850 UK GCSE

Problem 7Integers, Primes, HCF & LCM

Which of these numbers is prime?

Show answer & worked solution
  1. A. 5151
  2. B. 5757
  3. C. 5959✓ correct
  4. D. 6363

51=31751 = 3 \cdot 17, 57=31957 = 3 \cdot 19, 63=7963 = 7 \cdot 9.

5959 has no factor up to 59<8\sqrt{59} < 8, so 5959 is prime.

Problem #0851 UK GCSE

Problem 8Integers, Primes, HCF & LCM

Which is the prime factorisation of 6060?

Show answer & worked solution
  1. A. 2352 \cdot 3 \cdot 5
  2. B. 22352^2 \cdot 3 \cdot 5✓ correct
  3. C. 22152^2 \cdot 15
  4. D. 23352^3 \cdot 3 \cdot 5

60=230=2215=223560 = 2 \cdot 30 = 2 \cdot 2 \cdot 15 = 2^2 \cdot 3 \cdot 5.

Problem #0852 UK GCSE

Problem 9Order of Operations & Calculation

Work out 2+3×42 + 3 \times 4.

Show answer & worked solution
  1. A. 2020
  2. B. 1414✓ correct
  3. C. 99
  4. D. 1010

3×4=123 \times 4 = 12, then 2+12=142 + 12 = 14.

Problem #0853 UK GCSE

Problem 10Order of Operations & Calculation

Work out (5+1)2÷4(5 + 1)^2 \div 4.

Show answer & worked solution
  1. A. 99✓ correct
  2. B. 1.51.5
  3. C. 6.256.25
  4. D. 33

(5+1)2=62=36(5 + 1)^2 = 6^2 = 36, then 36÷4=936 \div 4 = 9.

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