If "the sum of 3 and a number is 16" is given, we can rewrite it as an equation (note that "a number" refers to a variable, commonly x):
3 + x = 16
Now, simply use the Subtraction Property of Equality (subtract 3 from both sides):
3 + x - 3 = 16 - 3
x = 13
Therefore, the number, or x, is equal to 13.
Hope this short response helps! :)
