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Worksheet

Problem-Solving Challenges — Calculating with Number

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Part A — Multi-Step Word Problems

Real problems rarely tell you which operation to use. Read carefully, decide what each step needs, and keep your working tidy so you can check it.

1 A book costs $24. The shop takes 25% off in a sale. How much do you save, and how much do you pay?
2 There are 240 students at a school. ¾ of them walk or cycle to school. How many is that? How many do not?
3 A recipe for 4 people needs 600 g of flour. How much flour is needed for 10 people? Show your reasoning.
4 Three friends share the cost of a $45 gift equally and also buy a card for $6 shared equally. How much does each friend pay in total?
5 Multi-step. A cinema sells 320 tickets. 40% are child tickets at $8 and the rest are adult tickets at $14. How much money is taken altogether?
6 Prove it. Leah says “finding 50% then 10% of a number is the same as finding 60%.” Is she right? Test it on $80 and explain.

Part B — Order of Operations & Mental Strategies

When an expression has several operations, we follow an agreed order: brackets first, then × and ÷ (left to right), then + and − (left to right). Smart mental strategies — doubling, halving, and compensation — can make hard calculations quick.

1 Evaluate, using the correct order of operations.

(a) 5 + 3 × 4 =

(b) (5 + 3) × 4 =

(c) 20 − 6 ÷ 2 + 1 =

2 Insert brackets to make each sentence true.

(a) 6 + 2 × 5 = 40

(b) 12 − 4 − 3 = 11

3 Use a smart mental strategy (doubling, halving or compensation) and explain it.

(a) 25 × 16 =

(b) 198 + 47 =

4 Estimate first, then calculate. For 312 × 19, write a sensible estimate, then the exact answer. How close were you?
5 Find the error. A student wrote 8 + 4 × 2 = 24. Explain the mistake and give the correct answer.
6 Open challenge. Using exactly four 4s and any operations and brackets, write an expression equal to 24. Can you find a second way?