42
2 when multiplied by 21 = 42
20/21 times 42 = 40
2+21=23 2*21=42 (* is another symbol for multiply)
1 x 42, 2 x 21, 3 x 14, 6 x 7
1 x 42, 2 x 21, 3 x 14, 6 x 7
1 x 42, 2 x 21, 3 x 14, 6 x 7, 7 x 6, 14 x 3, 21 x 2, 42 x 1.
1 x 42, 2 x 21, 3 x 14, 6 x 7, 7 x 6, 14 x 3, 21 x 2, 42 x 1
18 feet is 6 yards, and 21 feet is 7 yards. 6 multiplied by 7 is 42. Therefore, it's 42 square yards.
21 and 4 14 and 6 28 and 3 12 and 7 42 and 2
42 = 1 x 42, 2 x 21, 3 x 14, 6 x 7, 7 x 6, 14 x 3, 21 x 2, 42 x 1
42*18 = 756