The multiplication of two numbers with the same number of tens and the number of units equal to ten

1.

The multiplication of two numbers
with
the same number of tens
and
the number of units equal to ten

2.

The multiplication of two numbers with the same number of tens
and the number of units equal to ten
example first

3.

The multiplication of two numbers with the same number of tens
and the number of units equal to ten
71 . 79 =
7=7
1 + 9 = 10
7 . ( 7 + 1 ) = 7 . 8 = 56
1 . 9 = 09

4.

The multiplication of two numbers with the same number of tens
and the number of units equal to ten
example second

5.

The multiplication of two numbers with the same number of tens
and the number of units equal to ten
28 4 . 28 6 =
28 = 28
4 + 6 = 10
28 . ( 28 + 1 ) = 28 . 29 = 812
4 . 6 = 24