KA-0119Find what is actually being asked
3 points, difficulty 1 of 3Level 3–4about 45sBo has 24 marbles and gives a third of them to Ana. How many more marbles does Bo have than Ana now?
Hints
Take them one at a time. The first gives nothing away.
1A nudge
Read the last sentence again before you start.
2The strategy
The question is not how many Bo has. Work out both amounts, then answer the comparison that was actually asked for.
3The full solution
A third of 24 is 8, so Ana gets 8 and Bo keeps 16. The difference is 16 - 8 = 8.
Solution
The reliable way
A third of 24 is 8, so Ana receives 8 and Bo keeps 24 - 8 = 16. The question asks how many more Bo has, so subtract: 16 - 8 = 8. The transferable idea: read the final sentence before you begin, and underline the quantity it names - the number you naturally compute is often one step short of it.
The elegant way
Bo keeps two thirds and Ana gets one third, so the gap is one third of 24, which is 8.
Why this is on the test: Answering with the quantity you computed rather than the one that was asked for is the single most common way to lose an easy mark.