21
The multiples of 21 up to 500 are as follows: 21x1=21 21x2=42 21x3=63 21x4=84 21x5=105 21x6=126 21x7=147 21x8=168 21x9=189 21x10=210 21x11=231 21x12=252 21x13=273 21x14=294 21x15=315 21x16=336 21x17=357 21x18=378 21x19=399 21x20=420 21x21=441 21x22=462 21x23=483 21x24=504
21 times 5 = 105
35x3, 21x5 or 15x7
21x5 equals 105
21
The least common multiple is 105. (35x3 and 21x5)
Improve 21x1=21 21x2=42 21x3=63 21x4=84 21x5=105 21x6=126 21x7=147 21x8=168 21x9=189 21x10=210
Expressing each number as the product of prime numbers can help a lot:21 = 3x735 = 5x77 is the greatest common factor(H.C.F.) of 21 and 35.H.C.F.(21,35) = 7Method to find L.C.M. of x and y:L.C.M.(x,y) = H.C.F.(x,y) x Product of other no. in prime factorizations of x and ySo, L.C.M.(21,35) = H.C.F.(21,35) x 3x5 = 7x3x5 = 21x5 = 105.
The multiples of 21 up to 500 are as follows: 21x1=21 21x2=42 21x3=63 21x4=84 21x5=105 21x6=126 21x7=147 21x8=168 21x9=189 21x10=210 21x11=231 21x12=252 21x13=273 21x14=294 21x15=315 21x16=336 21x17=357 21x18=378 21x19=399 21x20=420 21x21=441 21x22=462 21x23=483 21x24=504
The least common multiple of 3, 5, and 7 is 105.This is the first number that each of these numbers have in common when finding the multiples of each number. You begin by taking each number and multiplying the number by 1, 2, 3, 4, 5, etc. until you come up with a number that is common to each of the numbers (3,5 and 7). In this case, the first number that the three numbers had in common happened to be 105. The number 3 had to be multiplied 35 times (35x3=105); The number 5 had to be multiplied 21 times (21x5=105); and the number 7 had to be multiplied 15 times to have a number in common with the other two numbers (15x7=105).