Question #016b1

1 Answer
Mar 15, 2017

#x >9#

Explanation:

Let the number be #x#

Four more than the number is #x+4#

The answer to the addition must be more than #13#

#x+4 > 13#

#x > 13-4#

#x >9#

So as long as you choose a number which is more than 9, when 4 is added, the result will always be more than 13.

Check:
Let #x = 11" " 11+4 = 15 and 15 >13#
Let #x = 9" " 9+4 = 13, " but " 13 = 13#

So, #9# does not work, but a number more than 9 will.