131313/707070+39393939/15151515
=13*10101/70*10101+39/15
=13/70+39/15 提取公因数约分
=13/70+13/5
=13*(1/70+1/5) 乘法分配率简便运算。
=13*(1/70+14/70)
=13*15/70
=13*3/14
=39/14
131313/70707+39393939/15151515
=13×10101/70×10101+13×3030303/5×3030303
=13/70+13/5
=13/70+182/70
=195/70
=39/14