How much is 2 * 4 of 2 + 4 * 6 of 2 + 6 * 8 of 2... + 96 * 98 of 2 + 98 * 100 of 2

How much is 2 * 4 of 2 + 4 * 6 of 2 + 6 * 8 of 2... + 96 * 98 of 2 + 98 * 100 of 2

1 / 2-1 / 4 = 2 * 4 / 2 (4-2) = 2 * 4 / 2
1 / 4-1 / 6 = 4 * 6 (6-4) = 4 * 6 (2)
.
2 * 4:2 + 4 * 6:2 + 6 * 8:2... + 96 * 98:2 + 98 * 100:2
=(1/2-1/4)+(1/4-1/6)+(1/6-1/8)+.+(1/96-1/98)+(1/98-1/100)
=1/2-1/100
=49/100