A number square has nine numbers in three rows and three columns.
The sums are at the edge, that is what each row and each column adds up to.
Some fields are empty. You have to find the missing numbers.
Example:
First row: 5 + 8 + ? makes 16. The 3 is missing, because 5 + 8 + 3 = 16.
First column: 5 + 6 + ? makes 16. The 5 is missing, because 5 + 6 + 5 = 16.
Always carry on where only one number is still missing.
The numbers filled in show the solution.
Example
- 3,7,5
For parents
What does this exercise practice?
Determine missing addends using row and column sums and practice bundling numbers.
Common pitfalls
Children sometimes add all three fields although one is still empty. Tip: first look for the row where only one number is missing, then work that one out.
How to practice at home
Lay out three rows of building blocks, count each row and each column. Cover one stack and have the missing amount guessed.
Related: Number square, Number cross, Table