21 x 20 = 420
150 x 20 = 3000
Estimating the product of 68 and 21 . . . It is easy in your head to think that this product would be close to 70 times 20. Again, in your head, you can figure that product to be 1400.
4 * 21 = 4 * (20 + 1) = 4*20 +4*1 = 80 + 4 = 84.
The product of 21 multiplied by 57 is 1,197.
The LCM of 20 and 21 is 420. The LCM of any pair of consecutive integers is their product.
The product of 52 and 21 is 1092
The product of 305 multiplied by 20 is 6,100.
Their product.
735
630
The product is: 18,669
The product is 7560