c) 93.32+14.16=93.2.16+14.16=16.(186+14)=16.200=3200

e)-8.40+2.108+24=24(9+1)-320=240-320=-80

b)86.15+150.1,4=86.15+15.14=15(86+14)=15.100=1500

d)98,6.199-990.9,86=98,6.199-99.98,6=98,6(199-99)=98,6.100=9860

f)993.98+21.331-50.99,3=993.(98+7-5)=993.100=99300

Tích giúp mình nha

b) Ta có: \(86\cdot15+150\cdot1.4\)

\(=86\cdot15+14\cdot15\)

\(=15\left(86+14\right)\)

=1500

c) Ta có: \(93\cdot32+14\cdot16\)

\(=186\cdot16+14\cdot16\)

\(=16\left(186+14\right)\)

\(=16\cdot200=3200\)

2A=1/2+1/6+1/12+1/20+1/30+1/42

    =1/1.2+1/2.3+1/3.4+1/4.5+1/5.6+1/6.7

    =1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7

    =1-1/7

    =6/7

A=1+18+124+148+180+1120A=1+18+124+148+180+1120

=1+12.4+14.6+16.8+18.10+110.12=1+12.4+14.6+16.8+18.10+110.12

=1+12(12−14+14−16+16−18+18−110+110−112)=1+12(12−14+14−16+16−18+18−110+110−112)

=1+12(12−112)=1+12(12−112)

=1+524=1+524

=2924

Tham khảo thôi nka

2A= 2/8+2/24+2/48+2/80= 2/(2*4)+2/(4*6)+2/(6*8)+2/(8*10)= 1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10= 1/2-1/10= 2/5 =>A= 1/5

\(A=\dfrac{1}{8}+\dfrac{1}{24}+\dfrac{1}{48}+\dfrac{1}{80}=\dfrac{1}{2\times4}+\dfrac{1}{4\times6}+\dfrac{1}{6\times8}+\dfrac{1}{8\times10}\)

\(2A=\dfrac{2}{2\times4}+\dfrac{2}{4\times6}+\dfrac{2}{6\times8}+\dfrac{2}{8\times10}\\ 2A=\dfrac{2}{2}-\dfrac{2}{4}+\dfrac{2}{4}-\dfrac{2}{6}+\dfrac{2}{6}-\dfrac{2}{8}+\dfrac{2}{8}-\dfrac{2}{10}\\ 2A=\dfrac{2}{2}-\dfrac{2}{10}=\dfrac{4}{5}\\ A=\dfrac{2}{5}\)

a,= 32.(11+67) +78.68

      32.78+78.68

      78.(32+68)

      78.100

      = 7800

b,76.(41-20)+21.24

   =76.21+21.24

   =21.(76+24)

   =21.100

   =2100

a: =-45*24+120

=-1080+120

=-960

b: =134(-1+51-48)

=134*2

=268

c: =-41*59-41*2+59*41-59*2

=-2(41+59)

=-200

g: =900x13

=11700

a)184 x 72 + 184 x 27 + 184

=184 x 72 + 184 x 27 + 184 x 1

= 184 x (72 + 27 + 1 )

=184 x 100=18400

c)1999 x 346 + 1999 + 653 x 1999

=1999 x 346 + 1999 + 653 x 1999 x 1

= 1999 x ( 346 + 653 + 1 )

= 1999 x 1000=1999000

e)23 x 5 x 7 x 4

= ( 23 x 7) x( 5 x 4)

= 161 x 20= 3220

b)1996 x 1257 – 1996 – 256 x 1996

=1996 x 1257 – 1996 – 256 x 1996 x 1

= 1996 x ( 1257 - 256 - 1 )

= 1996 x 1000= 1996000

a ) 184 x 72 +184 x 27 + 184 
 = 184 x ( 72 + 27 ) + 184
 = 184 x 99 + 184 
 = 18216 + 184
 = 18400
c) 1999 x 346 + 1999 + 653 x 1999
 = 1999 x ( 346 + 653 ) + 1999
 = 1999 x 999 + 1999
 = 1997001 + 1999 
 = 1999000
 e)  23 x 5 x 7 x 4
 = 23 x 7 x 5 x 4
 = 161 x 20
 = 3220
 b) 1996 x 1257 -1996 - 256 x 1996
 = 1996 x ( 1257 - 256 ) - 1996
 = 1996 x 1001 - 1996 
 = 1997996 - 1996
 = 1996000
 d) 24 x 89 + 24 + 16 x 15
 = 24 x 89 + 16 x 15 + 24
 = 2136 + 240 + 24
 = 2400
 g) 25 x 36 x 13
 = 25 x 36 x 13
 = 900 x 13
 = 11700
                                                        bài này làm hơi lâu nhưng khá dễ lần sau bạn nên tự
                                                       làm nha ♥♥

ta có : (ghi lại đề)

=6+12+18+24+30/3+6+9+12+15

=2*(3/3+6/6+9/9+12/12+15/15)

=2*(1+1+1+1+1)

=2*5=10

chúc main học tốt nhé

hi

a: \(19\cdot35+55\cdot81+19\cdot20\)

\(=19\cdot55+55\cdot81\)

\(=55\cdot100=5500\)

b: \(117\cdot98-117\cdot46-52\cdot17\)

\(=117\cdot52-52\cdot17\)

=5200

c: Số số hạng là:

\(\left(50-2\right):2+1=48:2+1=25\left(số\right)\)

Tổng là:

\(\dfrac{\left(50+2\right)\cdot25}{2}=\dfrac{52\cdot25}{2}=650\)

d: Số số hạng là:

50-11+1=40(số)

Tổng là:

\(\dfrac{\left(50+11\right)\cdot40}{2}=61\cdot20=1220\)