IB Math RevisionNumbers round and word scramble for IB Maths
A low-prep end-of-term lesson: six numbers, a target and 30 seconds to reach it, then a maths word scramble. Use the generator below for as many new rounds as you like.
- Level
- IB Maths SL and HL (AA and AI)
- Time
- 40 minutes, plus a 10-minute extension
- Topics
- Number and arithmetic; Mathematical vocabulary; Systematic searching
- Equipment
- No GDC: that’s the point.
Suggested timings
| Part | Time | What |
|---|---|---|
| Starter | 5 min | Quick questions on the board |
| Main: task A | 15 min | Numbers rounds |
| Main: task B | 10 min | Word scramble |
| Main: task C | 10 min | Small numbers, many targets |
| Extension | 10 min | Fast finishers or homework |
Starter (5 minutes)
Quick mental warm-up.
- Work out 75 × 4.
- Work out 100 − 37.
- Work out 8 × 25.
- Work out 450 ÷ 9.
Main activity (35 minutes)
Task A: Numbers rounds (15 min)
Use some or all of the six numbers, each at most once, with +, −, × and ÷ to make the target. Every step must give a positive whole number. Other ways are possible.
- Numbers: 100, 75, 6, 3, 8, 2. Target: 512.
- Numbers: 50, 25, 4, 7, 9, 1. Target: 331.
- Numbers: 75, 10, 5, 6, 2, 3. Target: 861.
- Numbers: 25, 8, 9, 3, 4, 1. Target: 247.
Task B: Word scramble (10 min)
Unscramble each set of nine letters to find a maths word.
- Unscramble: HTIGRALMO
- Unscramble: PONTEXENS
- Unscramble: QUESCENES
- Unscramble: DRUQATICA
Task C: Small numbers, many targets (10 min)
Use 1, 2, 3 and 4, each at most once, with +, −, ×, ÷ and brackets.
- Make 10.
- Make 24.
- Make 25.
Play more rounds
Each click makes a new round to put on the board. Every target can be made from the six numbers.
Word scramble
Unscramble the nine letters to find a maths word.
Extension (10 minutes)
For fast finishers.
- Using 1, 2, 3 and 4 (each at most once) with +, −, × and ÷, find the smallest whole number that cannot be made, and the largest number that can.
For teachers
Teacher notes and full worked answers
- How to play: put a round on the board, give 30 seconds, then ask for the closest result and the working. Exactly on target scores 10, within 5 scores 7, within 10 scores 5. Use the ‘Play more rounds’ generator on this page for as many new rounds as you like; every target it makes can be reached.
- Word scramble: one person reads the nine letters aloud, everyone writes the maths word. Ask for a one-line definition as a tie-break.
Starter
- 300
- 75 × 4 = 300
- 63
- 100 − 37 = 63
- 200
- 8 × 25 = 200
- 50
- 450 ÷ 9 = 50
Task A: Numbers rounds
- 8 × (75 − 6 − 3 − 2) = 512
- 75 − 6 − 3 − 2 = 64
- 8 × 64 = 512
- (50 + 25 − 7) × (4 + 1) − 9 = 331
- 50 + 25 − 7 = 68 and 4 + 1 = 5
- 68 × 5 = 340, and 340 − 9 = 331
- (75 + 5 + 6) × 10 + 3 − 2 = 861
- 75 + 5 + 6 = 86
- 86 × 10 = 860, and 860 + 3 − 2 = 861
- (25 + 8 + 1) × (4 + 3) + 9 = 247
- 34 × 7 = 238
- 238 + 9 = 247
Task B: Word scramble
- LOGARITHM
- Logarithm: the power a base is raised to, to give a number.
- EXPONENTS
- Exponents: powers, like the 3 in 23.
- SEQUENCES
- Sequences: ordered lists of numbers that follow a rule.
- QUADRATIC
- Quadratic: with a squared term, like x2 + 3x.
Task C: Small numbers, many targets
- 1 + 2 + 3 + 4 = 10
- Add them all.
- 1 × 2 × 3 × 4 = 24
- Multiply them all.
- (4 + 1) × (3 + 2) = 25
- 5 × 5 = 25
Extension
- 29 cannot be made; the largest is 36
- Every number from 1 to 28 can be made, for example 26 = (4 × 3 + 1) × 2, 27 = (4 × 2 + 1) × 3 and 28 = (3 × 2 + 1) × 4.
- The largest: (1 + 2) × 3 × 4 = 36. Checking every way to combine the four numbers shows 29 is impossible.
The same answers are in the answers PDF. Every answer was recomputed by computer before publishing.
Practise the topics
End-of-year quiz maths · Spot the mistake relay and maths taboo maths · Maths art maths · All themed maths
More for lessons: Weekly starters · Skill Builders · Free standard lessons · Worksheet builder · Competition maths