1 x 21, 3 x 7
To find the LCM of two numbers you need to multiply them together and then divide by the HCF. In this case, the numbers are coprime and so the HCF will be 1. Therefore was just have to multiply the numbers together: 7x3 = 21 And so the LCM of 7 and 3 is 21.
63
Any number can be multiplied by 21
How about: 3*7 = 21 or 1*21 = 21
21 multiplies to 21 to make it 441
21*5 is the answer
3 x 7 1 x 21
21
21*6=126
2*21 = 42
21 and 5
2 when multiplied by 21 = 42