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, 42, 63, 84.
There are 125 such numbers.
7, 14, 21 and just keep adding 7 until you get to 294.
21 , 42 , 63
if you know your threes just times it by numbers you know like, 6,8,20,50,90,120,140 and so on
just count by 3's upto 500. For Example: 3, 6, 9, 12, 15, 18, 21, 24, etc.....upto 500
They are: 7 14 21 28 and 35
21, 42, 63, 84.
There are 125 such numbers.
Just 63
7, 14, 21 and just keep adding 7 until you get to 294.
3, 6, 9, 12, 15, 18, 21.
21 and 42 are.
Way too many to list... 3 6 9 12 15 18 21 ...
21 , 42 , 63
21, 42, 63, 84
50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750.