(5/17 - 8/33) - (25/33 - 12/17) - 20230
câu trả lời cho câu hỏi của Huong Le Thị Lan: 1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32.
=(1+32)+(2+31)+(3+30)+(4+29)+(5+28)+(6+27)+(7+26)+(8+25)+(9+24)+(10+23)+(11+22)+(12+21)+(13+20)+(14+19)+(15+18)+(16+17)
=33+33+33+33+33+33+33+33+33+33+33+33+33+33+33+33. =33.16 (dấu chấm là dấu nhân)=528
wow! mù mắt. Ido tính toán có khác!
C2:(32+1)x32:2=528
bạn tính thử xem đúng đấy.
bài 1:
a) 10\17+5\-13-11\25+7\17-8\13
b) 0,3-93\7-70%0-4\7
c)1\8+1\24+1\48+...+1\2400
d) 3\41-12\17+33\49
-----------------------------
12\41-48\17+132\49
a, \(\dfrac{10}{17}\) + \(\dfrac{5}{-13}\) - \(\dfrac{11}{25}\) + \(\dfrac{7}{17}\) - \(\dfrac{8}{13}\)
= ( \(\dfrac{10}{17}\) + \(\dfrac{7}{17}\)) - ( \(\dfrac{5}{13}\) + \(\dfrac{8}{13}\)) - \(\dfrac{11}{25}\)
= \(\dfrac{17}{17}\) - \(\dfrac{13}{13}\) - \(\dfrac{11}{25}\)
= 1 - 1 - \(\dfrac{11}{25}\)
= - \(\dfrac{11}{25}\)
b, 0,3 - \(\dfrac{93}{7}\) - 70% - \(\dfrac{4}{7}\)
= 0,3 - 0,7 - ( \(\dfrac{93}{7}+\dfrac{4}{7}\))
= - 0,4 - \(\dfrac{97}{7}\)
= - \(\dfrac{2}{5}\) - \(\dfrac{97}{7}\)
= - \(\dfrac{499}{35}\)
c, \(\dfrac{1}{8}\) + \(\dfrac{1}{24}\) + \(\dfrac{1}{48}\)+ ...+ \(\dfrac{1}{2400}\)
= \(\dfrac{1}{2\times4}\) +\(\dfrac{1}{4\times6}\) + \(\dfrac{1}{6\times8}\) +...+ \(\dfrac{1}{48\times50}\)
= \(\dfrac{1}{2}\) \(\times\) ( \(\dfrac{2}{2\times4}\) +\(\dfrac{2}{4\times6}\)+ \(\dfrac{2}{6\times8}\) +...+ \(\dfrac{2}{48\times50}\))
= \(\dfrac{1}{2}\) \(\times\) ( \(\dfrac{1}{2}\) - \(\dfrac{1}{4}\) + \(\dfrac{1}{4}\) - \(\dfrac{1}{6}\) + \(\dfrac{1}{6}\) - \(\dfrac{1}{8}\) +...+ \(\dfrac{1}{48}\) - \(\dfrac{1}{50}\))
= \(\dfrac{1}{2}\) \(\times\) ( \(\dfrac{1}{2}\) - \(\dfrac{1}{50}\))
= \(\dfrac{1}{2}\) \(\times\) \(\dfrac{12}{25}\)
= \(\dfrac{6}{25}\)
tính nhanh
a . -17/25 . 20/33 + -17/25 . 13/3 + -3/25
b . 3 3/4 . 5 7/12 - 9 7/12 . 3 3/4
a/=\(\dfrac{-17}{25}\).(\(\dfrac{20}{33}+\dfrac{13}{3}\))+\(\dfrac{-3}{25}\)
=\(\dfrac{-17}{25}\).\(\dfrac{163}{33}\)+\(\dfrac{-3}{25}\)
=\(\dfrac{-2771}{825}\)+\(\dfrac{-3}{25}\)
=\(\dfrac{-574}{165}\)
KHÔNG BIẾT CÓ ĐÚNG KHÔNG NGHE
A.(13 9/11 : 38/49 - 5 5/11 : 38/49): (49/38•5/11)
B.39 124/173•95 4/23 + 75 49/173•18/23-39 124/173•94 9/23
C.(7/12+1 25/31)•19 3/8 - 7 1/12 • 7 3/8
D.17/35•37 19/25 + 1 8/17 • 33 7/25 +(17/35-1 8/17)•32 6/25
Mong mọi người giúp mình các bài này.Mai phải nộp bài gấp
mình còn ko bt cơ mà mai nộp r
mik chỉ lm đc 1 câu thôi mong bn like cho
(13911:3849−5211:3849):(4938.511)={(13+911).4938−(5+211).4938}:(4938.511)=4938.(13−5+911−211):(4938.511)=4938.(8+711):(4938.511)=(8+711):511=19
1/5*9+1/9*13+1/13*17+1/17*21+1/21*25+1/25*29+1/29*33+1/33*34
tính hợp lí ( nếu có thể)
a)18.17-3*6*7
b)33.(17-5)-7(33-5)
c) (-4-14):(-3)
d)(-25).12(-4).10
a> 18.17-3.6.7
= 18.17-18.7
= 18 ( 17-7)
= 18.10 = 180
đi giải tiếp
CÁC BẠN GIẢI GIÙM MÌNH NHA :
1,tính 1 cách hợp lí:
a, 25.(-7).4
b,33.(17-5)-17.(33-5)
a) \(25.\left(-7\right).4=\left(25.4\right).\left(-7\right)=100.\left(-7\right)=-700\)
b) \(33.\left(17-5\right)-17.\left(33-5\right)=33.17-33.5-17.33+17.5=5.\left(17-33\right)\)\(=5.\left(-16\right)=-80\)
Bài 2: ( 3 Điểm ) Thực hiện phép tính bằng cách hợp lí :
a) – (- 271) – ( 531 + 371 – 731 )
b) 33.( 17 – 5) – 17.( 33- 5).
c) ( - 32).( - 25 ).( - 123 ).125.