a) 5/2+3/2=8/2=4
b) 7/5+2/5+3/5=12/5
c) 5/4+5/6+5/12=(5*3+5*2+5)/12=(15+10+5)/12=30/12=5/2
d) 1/11+1/22+1/33=(1*6+1*3+1*2)/66=11/66
e)7/180+7/84+11/210=(7*7+7*15+11*6)/1260=(49+105+66)/1260=220/1260=
=11/63
f) 5/32+7/96+13/288=(5*27+7*9+13*3)/864=(135+63+39)/864=237/864
g) 19/(3²×2) +5/(2²×3²)=(19*2+5)/36=43/36