How do you divide 2 1/2 by 105????
2 + 1/2 = 5/2 so we have
5 /2 ÷ 105 =
5/2 ÷ 105 / 1 now.....invert the second fraction and multiply
5/2 x 1 / 105 = "cancel" 5 and 105 to 1 and 21
1/2 x 1 / 21 =
1 / 42
And there you go.....!!!