a) 930 + 257 . 5 - 405 : 9
= 930 + 1285 - 45
= 2215 - 45
= 2170
b) ( 857 + 936 ) . 15 - 92 . 30
= 1793 . 15 - 92 . 30
= 26895 - 2760
= 24135
c) 1/5 + 5/3 = 28/15
d) 3/4 + 9/3 - 1/4 = 7/2
e) 3/4 + 1 1 /2 + 0,5 : 5/12
= 3/4 + 3/2 + 6/5
= 69/20
hok tốt
a. 930 + 257 . 5 - 405 : 9
= 930 + 1285 - 45
= 2215 - 45
= 2170
b. (857 +936 ) . 15 - 92 . 30
= 1793 . 15 - 2760
= 26895 - 2760
= 24135
c. \(\frac{1}{5}+\frac{5}{3}\)
= \(\frac{3}{15}+\frac{25}{15}\)
= \(\frac{28}{15}\)
d. \(\frac{3}{4}+\frac{9}{3}-\frac{1}{4}\)
= \(\frac{9}{12}+\frac{36}{12}-\frac{3}{12}\)
= \(\frac{42}{12}=\frac{7}{2}\)
e.\(\frac{3}{4}+1\frac{1}{2}+0,5:\frac{5}{12}\)
= \(\frac{3}{4}+\frac{3}{2}+\frac{6}{5}\)
= \(\frac{15}{20}+\frac{30}{20}+\frac{24}{20}\)
= \(\frac{69}{20}\)
a) 930 + 257 . 5 - 405 : 9
= 930 + 1285 - 45
= 2215
b) (857 + 936) . 15 - 92 . 30
= 1793 .15 - 2760
= 26895 - 2760
= 24135
mk vừa mới đi làm đầu tháng trước, lun đi
\(a.\)\(930+257.5-405:9\)
\(=930+1375-45\)
\(=2305-45\)
\(=2260\)
\(b.\)\(\left(857+936\right).15-92.30\)
\(=1793.15-2760\)
\(=26895-2760\)
\(=24135\)
\(c.\)\(\frac{1}{5}+\frac{5}{3}\)
\(=\frac{3}{15}+\frac{25}{15}\)
\(=\frac{28}{15}\)
\(d.\)\(\frac{3}{4}+\frac{9}{3}-\frac{1}{4}\)
\(=\left(\frac{3}{4}-\frac{1}{4}\right)+\frac{9}{3}\)
\(=\frac{1}{2}+3\)
\(=3\frac{1}{2}\)hay \(\frac{7}{2}\)đều đc nha bn
\(e.\)Nhìn đề mk thấy chắc là thế này:
\(\frac{3}{4}+1\frac{1}{2}+0,5:\frac{5}{12}\)
\(=\frac{3}{4}+\frac{3}{2}+\frac{1}{2}.\frac{12}{5}\)
\(=\frac{3}{4}+\frac{3}{2}+\frac{6}{5}\)
\(=\frac{15}{20}+\frac{30}{20}+\frac{24}{20}\)( mẫu chung là 20 cho nhỏ nhé )
\(=\frac{69}{20}\)
~ rất vùi vì giúp đc bn ~
