To make adding larger numbers easier, you may use the compensation method, where you round up a number to make adding easier, and then take away the extra amount from the total result.
Example: 19+14
It is easier to do 20 + 14 = 34
Then take away the extra 1 (that made 19 into 20) to get: 34 - 1 = 33
Example: 397 + 225
It is easier to do 400 + 225 = 625
Then take away the extra 3 (that made 397 into 400) to get: 625 - 3 = 622
