KA-0114Money and change
3 points, difficulty 1 of 3Level 3–4about 60sThree notebooks cost 240 cents each. You pay with a 10 euro note. How many cents change do you get? One euro is 100 cents.
Hints
Take them one at a time. The first gives nothing away.
1A nudge
Work in cents all the way through.
2The strategy
Convert the note into cents so everything is in one unit, work out the total cost, and only then subtract. Check at the end whether you gave the cost or the change.
3The full solution
Three notebooks cost 3 x 240 = 720 cents, and 10 euros is 1000 cents, so the change is 1000 - 720 = 280 cents.
Solution— no shortcut on this one
Put everything in cents. Three notebooks at 240 cents cost 3 x 240 = 720 cents. A 10 euro note is 1000 cents. The change is 1000 - 720 = 280 cents. The transferable idea: convert to one unit before you start, and check at the end whether the question wanted the cost or the change.
Why this is on the test: Money questions combine a conversion and a which-number-did-they-ask trap, and both are worth a mark each across a paper.