What is partitioning?

Partitioning is a way of working out maths problems that involve large numbers by splitting them into smaller units so they’re easier to work with. So, instead of adding numbers in a column, like this…

  79
+34
113

…younger students will first be taught to separate each of these numbers into units, like this…

70 + 9 + 30 + 4

…and they can add these smaller parts together. For instance, they can pick out all the tens and work down to single units, making the problem more and more manageable, like this…

70 + 30 + 9 + 4 = 100 + 13 = 113

Partitioning can apply to numbers with decimals as well – by separating the decimals from the whole numbers according to the number of places used (so, .1 and .2 or .01 and .02), they can be added on their own before being joined to the final sum.

Why are children taught partitioning?

Children are taught this method before they learn to add numbers in columns. Partitioning gives children a different way of visualising maths problems, and helps them work out large sums in their head. By breaking numbers down into units that are easy for them (and us!) to calculate mentally, they can reach the correct answer without counting out tricky double or triple-digit numbers on their fingers or trying to remember where a decimal point needs to be.

Help your child practise partitioning with this handy worksheet.