简便计算:3/10+3/40+3/88+3/154
问题描述:
简便计算:3/10+3/40+3/88+3/154
答
=3/(2×5)+3/(5×8)+3/(8×11)+3/(11×14) =1/2-1/5+1/5-1/8+1/8-1/11+1/11-1/14 =1/2-1/14 =3/7
简便计算:3/10+3/40+3/88+3/154
=3/(2×5)+3/(5×8)+3/(8×11)+3/(11×14) =1/2-1/5+1/5-1/8+1/8-1/11+1/11-1/14 =1/2-1/14 =3/7