10 times
5
Once! After you have subtracted it once, you are subtracting 100 from 1900, and then 100 from 1800 and on and on
10
You can subtract 10 from 50 five times. Unless you're feeling rebellious and want to break the rules, then go ahead and subtract 10 as many times as your heart desires. Just don't come crying to me when you're left with a negative number and a bruised ego.
As many times as you feel like it before you get bored and stop. After 10 times, you will be left with zero, and you'll begin going into negative numbers. Bu that should be no problem for you. I thought that it would be only once because then you are subtracting from the number 90 not 100.
10 times.
-100
10 times
100 times 3 divided by 10 plus 25 subtract 5 EQUALS 50 unless there are parentheses...
10 times.. because.. 100 * 10 = 1000
9 times with a remainder of 10