1 + 5/21 + 2/15 = 1 + 5/21 + 2/15 = 1 + 5<em>15+2</em>215<em>15 + 2</em>215<em>15+2</em>21 / 21∗1521*1521∗15 = 1 + 75+4275 + 4275+42 / 315 = 1 + 117 / 315 = 315/315 + 117 / 315 = 315+117315 + 117315+117 / 315 = 432 / 315 = 24/35
1 + 5/21 + 2/15 = 1 + 5/21 + 2/15
= 1 + 5<em>15+2</em>215<em>15 + 2</em>215<em>15+2</em>21 / 21∗1521*1521∗15
= 1 + 75+4275 + 4275+42 / 315
= 1 + 117 / 315
= 315/315 + 117 / 315
= 315+117315 + 117315+117 / 315
= 432 / 315
= 24/35