Subtraction Tricks

An operation of finding an addend by a sum and another addend: 17 – 6 = 11.  Here 17 is a minuend,  6 – a subtrahend,  11 – the difference.

Math tricks 1: subtracting by oversubtracting
251-85
=(151+100)-85
=151+100-85
=151+15
=166
In this example,251 is break into 151 and 100
Math tricks 2:
subtracting by adding to each number
251-85
=(151+100)-85
=151+100-85
=151+15
=166
In this example,251 is break into 151 and 100
Math tricks 3:
subtracting by subtracting to each number
831-104
=(831-4)-(104-4)
=827-100
=727
In this example,251 is break into 151 and 100

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Easy way to check your answer: Check the answer by working backward
Example:

543 - 295 = 248

Add 248 to 295,and see whether you can get 543 back or not.

248 + 295 = 543

If the answer(eg.248) add with one of the numbers(eg.295) give you another numbers(eg.543),then your aswer is correct.