Friendly Number Tricks

Round one number to something easy, then adjust. For 298 + 457: treat 298 as 300, add to get 757, then subtract the 2 you added: 755. This "round and compensate" method turns ugly additions into simple ones. It works because addition is associative — rearranging the parts does not change the total.

Stacking friendly numbers also helps. For 47 + 36 + 53 + 14, rearrange: 47 + 53 = 100, 36 + 14 = 50. Total: 150. Spotting pairs that make round numbers is a skill that speeds up shopping, budgeting, and any situation where you add a list of values.