|History Of Math|
Math tricks 1:
Adding by breaking apart a number
In example here,break 137 to 122 and 15.
Math tricks 2:
Adding by overadding
In example here,97 was add to 100 first.
Easy way to check your answer:
Estimating the answer by rounding off numbers
249 rounds off to 250,159 to 160 and 504 to 500,then add up these figures.
The amount that has been estimated is 910,so the answer should be around 910.If your answer is only 800,then you know it is wrong.