113+59+71+57=? 113+59+71+57=\text{?} 113+59+71+57=?
In order to simplify our calculations we try to add numbers that give us a round result.
Let's keep in mind that:
113+57=170 113+57=170 113+57=170
59+71=130 59+71=130 59+71=130
Now we have a more manageable exercise to solve:
170+130=300 170+130=300 170+130=300
300