# Additions and subtractions up to 100

Additions and subtractions are more difficult with two-digit numbers.

Learn how additions and subtractions in column work.

## Notes

Discover how to do additions uo to 100 using the abacus.

Learn how to do additions and subtractions in column.

Discover the addends, the sum, the minuend, the subtrahend and the subtraction.

## Forward and backward on the number line

It's not easy to do additions and subtractions with larger numbers.

To calculate 8 + 7, let's think that 8 needs 2 units to arrive to 10. Then you add the other 5 units. The result is 15.

To calculate 16 - 7, let's start from 16 and subtract 6 units to arrive to 10 and then subtract another unit to arrive to 7. The result is 9.