3/28 + 3/70 + 3/130 +3/208 +3/304
=(1/4 -1/7)+(1/7 -1/10)+(1/10 -1/13)+(1/13 -1/16)+(1/16 -1/19)
=1/4 -1/7+1/7 -1/10+1/10 -1/13+1/13 -1/16+1/16 -1/19
=1/4 -1/19
=15/76
3/28 + 3/70 + 3/130 +3/208 +3/304
=(1/4 -1/7)+(1/7 -1/10)+(1/10 -1/13)+(1/13 -1/16)+(1/16 -1/19)
=1/4 -1/7+1/7 -1/10+1/10 -1/13+1/13 -1/16+1/16 -1/19
=1/4 -1/19
=15/76