This week’s sets of mental arithmetic questions concentrate solely on addition and subtraction. There are many different strategies that can be used, depending very much on the numbers involved.
For example:
7 plus 147 can be done quickly by counting on 7, or by knowing off by heart that 7 and 7 is 14
9 plus 129 can be done by adding 10 and subtracting 1
44 plus 16 can be done by adding the tens first and then the units, or vice versa.
It is important that children have all these techniques at their fingertips, and one way to make sure they have is to point out the many possible ways and which are the most efficient.
Year 3 mental arithmetic (sets 27 and 28)