The math factor pairs of 18 are (1,18) , (2,9) , (3,6) .
The factor pairs of 21 are:1, 213, 7Therefore, the number 21 has two pairs of positive integer factors.
There are two factor pairs of 21: 21 = 1 x 21 21 = 3 x 7
827 and 1.
1,8 2,4
(218,1)(109,2)
(49,1)(7,7)
10x1 1x105x22x5
1x125 5x25
1 and 73
(4,1)(2,2)