Giao diện mới của VnDoc Pro: Dễ sử dụng hơn - chỉ tập trung vào lớp bạn quan tâm. Vui lòng chọn lớp mà bạn quan tâm: Lưu và trải nghiệm

VnDoc.com

Bài 1.29 trang 22 SGK Toán 7 tập 1 KNTT

Bỏ dấu ngoặc rồi tính các tổng sau:

a) $\frac{{17}}{{11}} - \left( {\frac{6}{5} - \frac{{16}}{{11}}} \right) + \frac{{26}}{5}$ $\frac{{17}}{{11}} - \left( {\frac{6}{5} - \frac{{16}}{{11}}} \right) + \frac{{26}}{5}$

b) $\frac{{39}}{5} + \left( {\frac{9}{4} - \frac{9}{5}} \right) - \left( {\frac{5}{4} + \frac{6}{7}} \right)$ $\frac{{39}}{5} + \left( {\frac{9}{4} - \frac{9}{5}} \right) - \left( {\frac{5}{4} + \frac{6}{7}} \right)$

Xóa Đăng nhập để viết

3 Câu trả lời

Bé Cún
$\begin{array}{l}a)\frac{{17}}{{11}} - \left( {\frac{6}{5} - \frac{{16}}{{11}}} \right) + \frac{{26}}{5}\\ = \frac{{17}}{{11}} - \frac{6}{5} + \frac{{16}}{{11}} + \frac{{26}}{5}\\ = (\frac{{17}}{{11}} + \frac{{16}}{{11}}) + (\frac{{26}}{5} - \frac{6}{5})\\ = \frac{{33}}{{11}} + \frac{{20}}{5}\\ = 3 + 4\\ = 7\\b)\frac{{39}}{5} + \left( {\frac{9}{4} - \frac{9}{5}} \right) - \left( {\frac{5}{4} + \frac{6}{7}} \right)\\ = \frac{{39}}{5} + \frac{9}{4} - \frac{9}{5} - \frac{5}{4} - \frac{6}{7}\\ = (\frac{{39}}{5} - \frac{9}{5}) + (\frac{9}{4} - \frac{5}{4}) - \frac{6}{7}\\ = \frac{{30}}{5} + \frac{4}{4} - \frac{6}{7}\\ = 6 + 1 - \frac{6}{7}\\ = 7 - \frac{6}{7}\\ = \frac{{49}}{7} - \frac{6}{7}\\ = \frac{{43}}{7}\end{array}$ $\begin{array}{l}a)\frac{{17}}{{11}} - \left( {\frac{6}{5} - \frac{{16}}{{11}}} \right) + \frac{{26}}{5}\\ = \frac{{17}}{{11}} - \frac{6}{5} + \frac{{16}}{{11}} + \frac{{26}}{5}\\ = (\frac{{17}}{{11}} + \frac{{16}}{{11}}) + (\frac{{26}}{5} - \frac{6}{5})\\ = \frac{{33}}{{11}} + \frac{{20}}{5}\\ = 3 + 4\\ = 7\\b)\frac{{39}}{5} + \left( {\frac{9}{4} - \frac{9}{5}} \right) - \left( {\frac{5}{4} + \frac{6}{7}} \right)\\ = \frac{{39}}{5} + \frac{9}{4} - \frac{9}{5} - \frac{5}{4} - \frac{6}{7}\\ = (\frac{{39}}{5} - \frac{9}{5}) + (\frac{9}{4} - \frac{5}{4}) - \frac{6}{7}\\ = \frac{{30}}{5} + \frac{4}{4} - \frac{6}{7}\\ = 6 + 1 - \frac{6}{7}\\ = 7 - \frac{6}{7}\\ = \frac{{49}}{7} - \frac{6}{7}\\ = \frac{{43}}{7}\end{array}$
Trả lời hay
1 Trả lời 14/09/22
Bon
Cảm ơn nhé
Trả lời hay
1 Trả lời 14/09/22
Bọ Cạp
a) $\frac{{17}}{{11}} - \left( {\frac{6}{5} - \frac{{16}}{{11}}} \right) + \frac{{26}}{5}$ $\frac{{17}}{{11}} - \left( {\frac{6}{5} - \frac{{16}}{{11}}} \right) + \frac{{26}}{5}$
$= \frac{{17}}{{11}} - \frac{6}{5} + \frac{{16}}{{11}} + \frac{{26}}{5}$ $= \frac{{17}}{{11}} - \frac{6}{5} + \frac{{16}}{{11}} + \frac{{26}}{5}$
$= \left( {\frac{{17}}{{11}} + \frac{{16}}{{11}}} \right) + \left( { - \frac{6}{5} + \frac{{26}}{5}} \right)$ $= \left( {\frac{{17}}{{11}} + \frac{{16}}{{11}}} \right) + \left( { - \frac{6}{5} + \frac{{26}}{5}} \right)$
$= \frac{{33}}{{11}} + \frac{{20}}{5} = 3 + 4 = 7$ $= \frac{{33}}{{11}} + \frac{{20}}{5} = 3 + 4 = 7$
b) $\frac{{39}}{5} + \left( {\frac{9}{4} - \frac{9}{5}} \right) - \left( {\frac{5}{4} + \frac{6}{7}} \right)$ $\frac{{39}}{5} + \left( {\frac{9}{4} - \frac{9}{5}} \right) - \left( {\frac{5}{4} + \frac{6}{7}} \right)$
$= \frac{{39}}{5} + \frac{9}{4} - \frac{9}{5} - \frac{5}{4} - \frac{6}{7}$ $= \frac{{39}}{5} + \frac{9}{4} - \frac{9}{5} - \frac{5}{4} - \frac{6}{7}$
$= \left( {\frac{{39}}{5} - \frac{9}{5}} \right) + \left( {\frac{9}{4} - \frac{5}{4}} \right) - \frac{6}{7}$ $= \left( {\frac{{39}}{5} - \frac{9}{5}} \right) + \left( {\frac{9}{4} - \frac{5}{4}} \right) - \frac{6}{7}$
$\begin{matrix} = \dfrac{{30}}{5} + \dfrac{4}{4} - \dfrac{6}{7} = 6 + 1 - \dfrac{6}{7} \hfill \\ = 7 - \dfrac{6}{7} = \dfrac{{49}}{7} - \dfrac{6}{7} = \dfrac{{43}}{7} \hfill \\ \end{matrix}$ $\begin{matrix} = \dfrac{{30}}{5} + \dfrac{4}{4} - \dfrac{6}{7} = 6 + 1 - \dfrac{6}{7} \hfill \\ = 7 - \dfrac{6}{7} = \dfrac{{49}}{7} - \dfrac{6}{7} = \dfrac{{43}}{7} \hfill \\ \end{matrix}$
0 Trả lời 14/09/22