Sum and difference puzzles, step by step
Two numbers add up to 20.
How many apples are in each basket?
Two numbers from their total and their gap
- The question gives two facts and no numbers: they add to 14, and one is 2 more than the other. Everything below comes out of those two.
- Split the total evenly first. Half of 14 is 7, so 7 and 7 add up to exactly the right amount. That part is already correct, and it is where every answer to this kind of question starts.
- But those two are the SAME, and the question says one is 2 more than the other. So the even split is the right total with the wrong gap — it needs adjusting, not replacing.
- Move half the difference across. Half of 2 is 1: give it to one and take it from the other. Moving the WHOLE difference is the usual slip, and it opens a gap of 4.
- Check both facts, which is what makes this answer safe: 6 + 8 = 14, and 8 − 6 = 2.
How it works.
- 01
The question gives two facts and no numbers: they add to 14, and one is 2 more than the other. Everything below comes out of those two.
- 02
Split the total evenly first. Half of 14 is 7, so 7 and 7 add up to exactly the right amount. That part is already correct, and it is where every answer to this kind of question starts.
- 03
But those two are the SAME, and the question says one is 2 more than the other. So the even split is the right total with the wrong gap — it needs adjusting, not replacing.
- 04
Move half the difference across. Half of 2 is 1: give it to one and take it from the other. Moving the WHOLE difference is the usual slip, and it opens a gap of 4.
- 05
Check both facts, which is what makes this answer safe: 6 + 8 = 14, and 8 − 6 = 2.