The number of children in 1988 is:

From above given table , we have
Total population in 1988 = 146947
Total number of men = 65104
Total number of women = 60387
The number of children in 1988 = Total population in 1988 − ( Total number of men in 1988 + Total number of women in 1988 )
= 146947 − (65104 + 60387) = 21456.