Identify the keywords and think, which operation do we need to use.

First add ones to the number and then tens.

Add 1,300 to 8,890, then take away 1 ones.

Add tens and ones separately.

Identify the keywords and think, which operation do we need to use.

Add hundreds, tens and ones separately.

Think of the closest easy number to 999.

Take 87 as 80 and 7, then subtract 80 first from 112.

First add ones to the number and then tens.

Subtract 100 from 503, then add 1.