a)300

b)374

c)4747

d)4530

e)2250

g)123123

Đây là toán lớp 4

a) 300

b) 374

c) 4747

d) 4530

e) 2250

g) 123123

a) 25 x 12 = 25 x 4 x 3 = 100 x 3 = 300

b) 34 x 11 = 34 x ( 10 + 1 ) = 34 x 10 + 34 x1 = 340 + 34 = 374

c) 47 x 101 = 47 x ( 100 + 1 ) = 47 x 100 + 47 x 1 = 4700 + 47 = 4747

d) 15 x 302 = 15 x ( 300 + 2 ) = 15 x 300 + 15 x 2 = 4500 + 30 = 4530

g) 123 x 1001 = 123 x ( 1000 + 1 ) = 123 x 1000 +123 x 1 = 123000 + 123 = 123123

a)[(-7)+(-93)]+[(-125)+(-25)

=-100+-150

=-250

b)2012+(-1000)+(-12)+(-500)

=[2012+(-12)]+[(-1000)+(-500)]

=2000+-1500

=-500

c)(-12).7+(-8).7+4.(-25)+(-6).(-25)

=7[(-12)+(-8)]+-25[4+-6]

=7.(-20)+-25.-2

=-140+50

=-90

a) (-7) + (-125) + (-93) + (-25)

= -7 - 125 - 93 - 25

= (-7 - 93) - (125 + 25)

= -100 + (-150)

= -250

b) 2012 + (-1000) + (-12) + (-500)

= (2012 - 12) - (1000 + 500)

= 2000 - 1500

= 500

c) (-12).7 + (-8).7 + 4.(-25) + (-6) . (-25)

= (-12 + (-8) . 7 + (4 + (-6) . (-25)

= -20 .7 + (-2) . (-25)

= -2 . 10 . 7 + (-2)  . 25

= -2 . 70 + (-2) . 25

= -2 . (70 + 25)

= -2 . 95

= -190

Bài 1

a)(-7)+(-125)+(-93)+(-25)

   =(-7)+(-93)+(-125)+(-25)

   =(-100)+(-150)

   =-250

b)2012+(-1000)+(-12)+(-500)

   =2012+(-12)+(-1000)+(-500)

   =2000+(-1500)

   =500

c)(-12).7+(-8).7+4.(-25)+(-6).(-25)

   =7.[(-12)+(-8)]+(-25).[4+(-6)]

   =7.(-20)+(-25).(-2)

   =(-140)+50

   =(-90)

a, \(\frac{2}{3}\).\(\frac{15}{17}\)+\(\frac{2}{3}\).\(\frac{2}{17}\)

= \(\frac{2}{3}\).( \(\frac{15}{17}\)+ \(\frac{2}{17}\))

= \(\frac{2}{3}\). 1

=\(\frac{2}{3}\)

b,\(\frac{20}{19}\):\(\frac{3}{7}\)- \(\frac{1}{19}\): \(\frac{3}{7}\)

= ,\(\frac{20}{19}\).\(\frac{7}{3}\)- \(\frac{1}{19}\).\(\frac{7}{3}\)

= \(\frac{7}{3}\).(\(\frac{20}{19}\)-\(\frac{1}{19}\))

=\(\frac{7}{3}\).1

=\(\frac{7}{3}\)

Mn đã trả lời rùi mà~

A. \(\frac{2}{3}.\frac{15}{17}+\frac{2}{3}.\frac{2}{17}\)

=\(\frac{2}{3}.\left(\frac{15}{17}+\frac{2}{17}\right)\)

=\(\frac{2}{3}.1\)

=\(\frac{2}{3}\)

B. \(\frac{20}{19}:\frac{3}{7}-\frac{1}{19}:\frac{3}{7}\)

=\(\left(\frac{20}{19}-\frac{1}{19}\right):\frac{3}{7}\)

=1:\(\frac{3}{7}\)

=\(\frac{7}{3}\)

( 9 x 4 - 36 ) : ( 7 x 8 x 9 x10 x11 x12 )

= ( 36 - 36 ) :                 A

=        0        :                 A

=                0

=(36-36):(7x8x9x10x11x12)

=0:(7x8x9x10x11x12)

=0

12.(38 - 15) - 38.(12 + 15)

= 12. 38 - 12. 15 - 38. 12 - 38. 15

= 15.(12 + 38)

= 15. 50

= 750

\(\frac{-15}{4}\times\frac{9}{11}+\frac{15}{4}\times\frac{15}{11}-\frac{15}{4}\times\frac{6}{11}\)

\(=\frac{15}{4}\times\left(\frac{-9}{11}+\frac{15}{11}-\frac{6}{11}\right)\)

\(=\frac{15}{4}\times0\)

\(=0\)

\(=\frac{15}{4}\times\left(-\frac{9}{11}\right)+\frac{15}{4}\times\frac{15}{11}+\frac{15}{4}\times\left(-\frac{6}{11}\right)\)

\(=\frac{15}{4}\times\left(-\frac{9}{11}+\frac{15}{11}+\left(-\frac{6}{11}\right)\right)\)

\(=\frac{15}{4}\times0\)

\(=0\)

v

\(\dfrac{11}{4}-\dfrac{9}{8}=\dfrac{22-9}{8}=\dfrac{13}{8}+\dfrac{15}{12}=\dfrac{156+120}{96}=\dfrac{276}{96}\)

\(\dfrac{126}{84}+\dfrac{5}{3}=\dfrac{378+420}{252}=\dfrac{798}{252}\)

\(\dfrac{13}{18}:\dfrac{5}{9}=\dfrac{13.5}{18.9}=\dfrac{615}{162}-\dfrac{1}{1}=\dfrac{615-162}{162}=\dfrac{453}{162}\)

\(\dfrac{3}{9}+\dfrac{45}{12}=\dfrac{36+405}{108}=\dfrac{441}{108}\)

a,11/4−9/8+15/12

=    13/8    + 15/12 

=  276/96

= 29/8

b,6/7x21/12+5/3

=  126/84 +  5/3

=   798/252

=         

c,13/18:5/9−1

=   615/162- 1

=  453/162

d,3+9/4:3/5

=  3 + 45/12

= 441/108

 kết quả bằng 1968

2*31*12+46*96+8*27*3 = 5808

hok tốt

#sakurasyaoran