29 divided by 6 equals 4
21/4 = 5.25
4 with remainder 4.
4 goes into 84 = 21
4, remainder 16
Exactly 21 of them
4 with remainder 1
4 will go into 84 21 times
4 x 21 = 84 with a remainder of 9
4 with remainder 1.
87 ÷ 4 = 21 remainder 3
4 with remainder 4.