25 × 32 × 2 × 4

= (25 x 4) x (32 x 2)

= 100 x 64

= 6400

=6400

a,16+25+30+54

=(16+54)+(25+30)

=70+55

=125

b,25+43+57+32

=(25+32)+(43+57)

=57+100

=157

16 + 25 + 30 + 54 

= ( 16 + 54 ) + (25 + 30  ) 

= 70 + 55

= 125 

25 + 43 + 57 + 32 

= ( 43 + 57 ) + ( 25 + 32 ) 

= 100 + 57 

= 157 

a) 16+25+30+54=125

b) 25+43+57+32=157

\(\left(25\times32\right)\div4\\ =25\times32\div4\\ =25\times\left(32\div4\right)\\ =25\times8\\ =200\)

`(25 \times 32) \div 4`

`= (25 \times 4 \times 8) \div 4`

`= (100 \times 8) \div 4`

`= 800 \div 4`

`= 200`

\(A=1+\dfrac{1}{5}+\dfrac{1}{25}+\dfrac{1}{125}+...+\dfrac{1}{625}+\dfrac{1}{78125}\)

\(=1+\dfrac{1}{5}+\dfrac{1}{5^2}+\dfrac{1}{5^3}+...+\dfrac{1}{5^7}\)

\(5A=5+1+\dfrac{1}{5}+\dfrac{1}{5^2}+...+\dfrac{1}{5^6}\)

\(\Leftrightarrow5A-A=5+1+\dfrac{1}{5}+\dfrac{1}{5^2}+...+\dfrac{1}{5^6}-1-\dfrac{1}{5}-\dfrac{1}{5^2}-\dfrac{1}{5^3}-...-\dfrac{1}{5^7}\)

\(\Leftrightarrow4A=5-\dfrac{1}{5^7}\Leftrightarrow A=\dfrac{5-\dfrac{1}{5^7}}{4}=\dfrac{\dfrac{390624}{78125}}{4}=\dfrac{390624}{312500}=\dfrac{97656}{78125}\)

= 1324x( 65+ 52 - 17 )

= 1324x100

= 132400

a) 1324 x 65 + 1324 x 52 - 17 x 1324

= 1324 x (65 + 52 - 17)

= 1324 x 100

= 132400.

b) 25 x 32 x 2 x 4

= (25 x 4) x (32 x 2)

= 100 x 64

= 6400.

=132400

(689 + 875) + 125 = 689 + (875 + 125) = 689 + 1000 = 1689

c) 25

a) \(31\cdot72+\left(-31\right)\cdot70-2\cdot70\)

\(=31\cdot72-31\cdot70-2\cdot70\)

\(=31\cdot\left(72-70\right)-2\cdot70\)

\(=31\cdot2-2\cdot70\)

\(=2\cdot\left(31-70\right)\)

\(=2\cdot-39\)

\(=-78\) 

b) \(25\cdot\left(32+17\right)-32\cdot\left(25+47\right)\)

\(=25\cdot32+25\cdot17-32\cdot25-32\cdot47\) 

\(=25\cdot\left(32-32+17\right)-32\cdot47\)

\(=25\cdot17-32\cdot47\)

\(=425-1504\)

\(=-1079\)

\(a,50\%+\dfrac{7}{12}-\dfrac{1}{2}\\ =\dfrac{1}{2}+\dfrac{7}{12}-\dfrac{1}{2}\\ =\left(\dfrac{1}{2}-\dfrac{1}{2}\right)+\dfrac{7}{12}\\ =\dfrac{7}{12}\\ b,2022\times67+2022\times43-2022\times10\\ =2022\times\left(67+43-10\right)\\ =2022\times100\\ =202200.\\ c,125-25:3\times12\)

\(=25\times5-25:3\times12\\ =25\times\left(5-\dfrac{1}{3}\right)\times12\\ =25\times\dfrac{14}{3}\times12\\ =1400\)

a,50%+127​−21​=21​+127​−21​=(21​−21​)+127​=127​b,2022×67+2022×43−2022×10=2022×(67+43−10)=2022×100=202200.c,125−25:3×12

=25×5−25:3×12=25×(5−13)×12=25×143×12=1400=25×5−25:3×12=25×(5−31​)×12=25×314​×12=1400

a) 7/12

b) 202200

c) 1400

d) mình ko bt