=7.38*(1.25*80)

=7.38*100

=738

7,38x1,25x80

=7,38x(1,25x80)

=7,38x100

=738

a. $\dfrac{14}{15}+\dfrac{2}{11}+\dfrac{1}{15}+\dfrac{4}{11}+\dfrac{10}{22}$

$=(\dfrac{14}{15}+dfrac{1}{15})+(\dfrac{2}{11}+\dfrac{4}{11}+\dfrac{10}{22})$

$=1+1=2$

b. $74\times43-43+27\times43$

$=(74-1+27)\times43$

$=100\times43=4300$

\(a)\dfrac{14}{15}+\dfrac{2}{11}+\dfrac{1}{15}+\dfrac{4}{11}+\dfrac{10}{22}\)

\(=\left(\dfrac{14}{15}+\dfrac{1}{15}\right)+\dfrac{2}{11}+\dfrac{4}{11}+\dfrac{5}{11}\)

\(=1+1=2\)

\(b)74\times43-43+27\times43\)

\(=43\times\left(74-1+27\right)\)

\(=43\times100=4300\)

\(\left(1+\frac{1}{2}\right)\times\left(1+\frac{1}{3}\right)\times\left(1+\frac{1}{4}\right)\)

\(=\frac{3}{2}\times\frac{4}{3}\times\frac{5}{4}\)

\(=\frac{5}{2}\)

p/s: chúc bạn học tốt

a)=2

b)=1/3

A = \(\dfrac{36\times950+18\times726\times2+3\times324\times12}{1+3+5+7+...+27+29+31-152}\)

A = \(\dfrac{36\times950+36\times726+36\times324}{1+3+5+7+...+27+29+31-152}\)

MS = 1 + 3 + 5 +...+ 27 + 29 + 31 - 152

Xét dãy số: 1; 3; 5;...;27; 29; 31 là dãy số cách đều với khoảng cách là:  

                    3 - 1 = 2

Số số hạng của dãy số là: 

                 (31 - 1): 2 + 1 = 16

MS = (31 + 1) x 16 : 2 - 152 = 104

A = \(\dfrac{36\times\left(950+726+324\right)}{104}\)

A = \(\dfrac{36\times2000}{104}\)

A = \(\dfrac{9000}{13}\)

9.5(3.7+4.3+2)=9.5 x 10=95

95

Trả lời:

1/3+1/2+1/5+12/15+22/33+16/32=

(1/3+22/33)+(1/5+12/15)+(1/2+16/32)

=1+1+1=3