A calculation square has four or nine numbers in rows and columns.
The sums are shown at the edge, so what each row and each column add up to.
Some fields are empty. You have to find the missing numbers.
Example:
First row: 5 + 8 + ? gives 16. The 3 is missing, because 5 + 8 + 3 = 16.
First column: 5 + 6 + ? gives 16. The 5 is missing, because 5 + 6 + 5 = 16.
Always keep calculating where only one number is still missing.
The numbers filled in show the solution.
Examples
Example: Big Calculation Square
Example: Small Calculation Square
For parents
What does this exercise practice?
Determine missing addends using row and column sums and practice grouping numbers.
Common pitfalls
Children sometimes add up all three fields even though one is still empty. Tip: first find the row where only one number is missing, then work it out.
How to practice at home
Lay out three rows with building blocks, count each row and each column. Cover one stack and let your child guess the missing number.
Related: Arrow arithmetic, Math Table, Number Wall