Question

how can u add and subtract two four digit number multiplies of 100 explain breifly

Answer 1

We can subtract two 4 digit multiples of 100 ( say 2000 and 5600 ) in an easier way rather than 5600 + 2000. That is, to divide the numbers by hundred, subtract or add them whatever is necessary, and then multiply it by 100.
Eg : 5600 / 100 = 56
       2000 / 100 = 20
Add : ( 56 + 20 ) * 100
         = 76 * 100
         = 7600
Or Subtract : ( 56 - 20 ) * 100
                    = 36 * 100
                    = 3600

Answer 2

just add or subtract two numbers and eventually when you find the answer multiply it by 100