Question

вычислите: 12+13;13-14;14+15;15-16

Answer 1

1/2+1/3=3/6+2/6=5/6
1/3-1/4=4/12-3/12=1/12
1/4+1/5=5/20+4/20=9/20
1/5-1/6=6/30-5/30=1/30