A number decreased by 5 is 50

55 decrease by 5 is 50, or 55 - 5 = 50.

Step-by-step explanation:

Let x represent the missing number.

When you hear the words decrease, minus, that tells you to subtract.

Before we subtract, if there is a variable, we must do the opposite of subtraction, we need to add.

50 + 5 = x

Which means x = 50 + 5.

50 + 5 = 55.

Therefore, x = 55.