If a kindergarten teacher seats the class with four children on each rows there will be three children who will not have a seat however if five children are seated in each row there will be two empty seats what is the least number of children the class would have?

your number when divided by 4 leaves a remainder of 3

when divided by divided by 5, leaves a remainder of 2

numbers which fit the first case:
7 11 15 19 23 27 31 35 39

numbers which fit the 2nd case:
7 12 17 22 27

the least number would be 7, but I have a feeling they are looking for 27

check:
7 ---> one row of 4, with 3 left over
7 ---> one row of 5, with 2 left over

27 ---> 6 rows of 4, with 3 left over
27 ---> 5 rows of 5, with 2 left over