Question

Tinh tổng : a.1/3 + 1/16 + 1/18 .                              b. 1/12 + 1/16 +3/4Tinh bằng cách thuận tiện nhất             a. 1/15+4/15+5/18+7/18                      b. 1/8 + 1/12 + 3/8 + 5/12 .                   

 

Answer 1

1. = 1+2+3/7 = 6/7

2. = (3/7+4/7) + (4/9+5/9) = 1+1 = 2

Tk mk nha

Answer 2

\(\frac{1}{7}+\frac{2}{7}+\frac{3}{7}=\frac{1+2+3}{7}=\frac{6}{7}\)

\(\frac{3}{7}+\frac{4}{9}+\frac{4}{7}+\frac{5}{9}\)

\(=\left(\frac{3}{7}+\frac{4}{7}\right)+\left(\frac{4}{9}+\frac{5}{9}\right)\)

\(=1+1\)

\(=2\)

Answer 3

1) \(\frac{1}{7}+\frac{2}{7}+\frac{3}{7}=\frac{6}{7}\)

2) \(\frac{3}{7}+\frac{4}{9}+\frac{4}{7}+\frac{5}{9}\)

\(=\left(\frac{3}{7}+\frac{4}{7}\right)+\left(\frac{5}{9}+\frac{4}{9}\right)\)

\(=\frac{7}{7}+\frac{9}{9}\)

\(=1+1=2\)