well if you really don't know it's 72 i learn in the 4th grade.
Learn your multiplication tables.
Here is the 8 times table. followed by the 9 times table.
1 x 8 = 8
2 x 8 = 16
3 x 8 = 24
4 x 8 = 32
5 x 8 = 40
6 x 8 = 48
7 x 8 = 56
8 x 8 = 64
9 x 8 = 72 ( Note for the question answer)
10 x 8 = 80
11 x 8 = 88
12 x 8 = 96
1 x 9 = 9
2 x 9 = 18
3 x 9 = 27
4 x 9 = 36
5 x 9 = 45
6 x 9 = 54
7 x 9 = 63
8 x 9 = 72 ( Note for the question answer)
9 x 9 = 81
10 x 9 = 90
11 x 9 = 99
12 x 9 = 108
NB Only in the 9 times table, if you add the digits of the answers they always add to '9'. e.g. 72 ; 7 + 2 = 9
Read & learn by heart all your multiplication tables. It will make your arithmetic much easier.
9
80 Γ· 9 = 8 remainder 8
7 goes into 56 8 times56 / 7 = 8
The product of 7*8*9 = 504
72... 8 goes into 72, 9 times 9 goes into 72, 8 times and 6 goes into 72, 12 times
8 goes into 78 nine times with a remainder of 6, which is the same as 9 3/4 times.
80 Γ· 9 = 8 remainder 8
7 goes into 56 8 times56 / 7 = 8
6 goes in 12 times. 8 goes in 9 times. 9 goes in 8 times.
The product of 7*8*9 = 504
72... 8 goes into 72, 9 times 9 goes into 72, 8 times and 6 goes into 72, 12 times
8 x 1/9 = 8/9
8 goes into 78 nine times with a remainder of 6, which is the same as 9 3/4 times.
It is: 3 times 8/9 = 8/3 simplified
9 goes into 72 exactly 8 times
9 x 8 = 72
8 times 9 72
It is: 8 times 9 = 72