a,4x7x5x5x9

=(4x5)x(9x5)x7

=20x45x7

=900x7=6300

a.

\(4\times183\times25=4\times25\times183=100\times183=18300\)

b.

\(165\times59+165\times165\times40=165\times\left(59+1+40\right)=165\times100=16500\)

c.

\(56\times49:7=56\times\left(49:7\right)=56\times7=392\)

d.

\(67\times15-57\times15=15\times\left(67-57\right)=15\times10=150\)

a) 19,17x25x4=19,17(25x4)=19,17x100=1917

b)1,79x(8x125)=1,79x1000=1790

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2 câu đấy à?

\(125+173+175+27=\left(125+175\right)+\left(173+27\right)=300+200=500\)

\(125\times75+125\times25=125\times\left(75+25\right)=125\times100=12500\)

1/4

\(=\dfrac{8}{15}\left(\dfrac{25}{32}-\dfrac{10}{32}\right)=\dfrac{8}{15}\cdot\dfrac{15}{32}=\dfrac{1}{4}\)

( 25/32 - 10/32) x 8/15

 = 15/32 x 8/15

= 1/4

a: =1250:25=50

b: =234(45+55)+234=23400+234=23634

c: =1000x1000=1000000

30x25x7x8

=(30x7)x(25x8)

=210x200

=42000

75x8x12x14

=(75x12)x(8x14)

=900x112

=100800

A) =(30*7)*(25*8)

=210*200

=4200 

B)=(75*8)*(12*14)

=600*168
=100800

= 25 x 75/100 + 75 x 0.92 + 25 x 0.25 + 75 x 8/100
= 25 x 0.75 + 75 x 0.92 + 25 x 0.25 + 75 x 0.08
= 25 x ( 0.75 + 0.25 ) + 75 x ( 0.92 + 0.08 )
= 25 x 1 + 75 x 1 
= ( 25 + 75 ) x 1 
= 100 x 1
= 100

b. 2 x 8 x 50 x 25 x 125 = (2 × 50) × (8 × 125) × 25

= 100 × 1000 × 25

= 100000 × 25

= 2500000