Start with the head: take the first part and see how much is still missing.
You have to make that rest from body and legs - only a few options there.
If it does not work out, take the next head part. That way you try everything in order instead of guessing.
Example
- 1, 2, 2
- 1, 1, 1
For parents
What does this exercise practice?
Building heroes practises systematic trial and splitting a target number into exactly three addends.
Common pitfalls
Unlike free addition it has to be exactly three parts - one from each column. Two parts on their own do not count.
How to practice at home
Make three piles of numbered slips and take turns hitting a target number - exactly one slip from each pile.