13)

According to the meaning, m+(2m+ 1)=7.

Solution: m=2

14)

Both the absolute value and the complete square are 0,

Then the sum is 0, so:

a+ 1=0

b-2=0

Solution: a=- 1, b=2.

The number of single item a+b+b+ 1 =4.

The number of singles is 4.