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About this video
A whole Grade 8 Term 1 prep test worked through: multiple choice, whole numbers (primes, HCF and LCM from factor trees, ratio, simple interest, speed), integers and common fractions — and when the calculator is allowed versus when every step must be shown.
What it covers
- Multiple choice: when the calculator is allowed
- HCF and LCM from factor trees
- Sharing in a ratio, simple interest and speed
- Integers: two signs next to each other, and BODMAS
- Fractions: mixed numbers, the reciprocal, increasing by a percentage
Extra worked examples
✍️ Extra example: find the HCF and the LCM of 84 and 90 using factor trees
- 184 = 2 × 2 × 3 × 7Divide by the smallest prime that goes in, again and again.
- 290 = 2 × 3 × 3 × 5The same for 90.
- 3HCF = 2 × 3 = 6Only the primes that appear in BOTH numbers.
- 4LCM = 2 × 2 × 3 × 3 × 5 × 7 = 1 260Every prime, as many times as it appears MOST in either number. Check: 1 260 ÷ 84 = 15 and 1 260 ÷ 90 = 14 ✓
✍️ Extra example: calculate 2⅓ ÷ 1⅘ (show all your working)
- 12⅓ = 7/3 and 1⅘ = 9/5Mixed numbers become improper: the whole times the denominator, plus the numerator.
- 27/3 × 5/9Dividing by a fraction is multiplying by its RECIPROCAL — swap its top and bottom.
- 3= 35/27Multiply the tops and the bottoms; 35 and 27 share no factor, so it is done.
Exercises to try
Work each one out, then click to reveal the answer.
- 1List the prime numbers between 50 and 60.
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53 and 59 — each has only two factors, 1 and itself - 2A class has 32 learners, and girls : boys = 3 : 5. How many girls and how many boys are there?
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3 + 5 = 8 parts: 3/8 × 32 = 12 girls and 5/8 × 32 = 20 boys - 3Calculate the simple interest on a loan of R6 000 at 11% per year for 3 years, and the total paid back.
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I = (6 000 × 11 × 3) ÷ 100 = R1 980; total = R6 000 + R1 980 = R7 980 - 4Calculate (−3) × (−4) − 20 ÷ (−5).
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12 − (−4) = 12 + 4 = 16 (× and ÷ before −) - 5Increase R2 500 by 12%.
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12/100 × 2 500 = R300 → R2 500 + R300 = R2 800
Practise this topic
Download matching Grade 8 papers and worksheets.
