Activity: Addition and subtraction methods. ... To solve this you can count up from 4980 to 5000 (which is 20). Then you can count on from 5000 to 5125 (which is 125).

In this KS2 Maths article you'll find out how to use mental methods when doing addition and subtraction in your head. We also have KS2 Maths videos, a quiz and lots of examples.