First, 7 x 10 = 70, you now have 30 left, 7 x 4 = 28. 10 + 4 = 14 with a remainder of 2. That is your answer though many would put “14 2/7” as the answer with the 2 over the 7 because its the remainder over what was getting divided first. thus 100/7 is has the remainder of 2 with the quotient 14.
