Ineed to check a number line of 0 to 4 using 1/3

Draw a straight line. Label the left side "0" and then make lines with
"2" "3" and "4".

1/3 means it i 1/3rd of 1. Which means you need to divide everything from 0 - 1 into 2 segments. The first segment on the left side is your 1/3rd spot. The next one is your 2/3rd place, and then finally the 1 is your 3/3 (or one whole.)

Letter c i’d say

31 is prime. and it’s prime factorization is just 31.