Tính Nhanh
a) 254x399–145 / 254+399 x 253=
b) 5932+6001x5931 / 5932+6001-69
c) C=(1 – 1/2) x ( 1 - 1/3) x (1 – 1/4) x (1 – 1/5) x (1 – 1/6) x ………..
x ( 1 - 1/2015 ) x ( 1- 1/2016)
Bài 6: Tính nhanh:
a) \(\dfrac{254x399-145}{254+399x253}\) ( x ở trong bài này là nhân ạ)
b) \(\dfrac{5932+6001x5931}{5932x6001-69}\)
c) \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{16}\) + \(\dfrac{1}{32}\)
a) \(=\dfrac{254x\left(400-1\right)-145}{254+\left(400-1\right)x253}=\dfrac{254x400-254-145}{254+253x400-253}\)
\(=\dfrac{101600-399}{101200+1}=\dfrac{101211}{101201}=\dfrac{101201+10}{101201}=1+\dfrac{10}{101201}\)
b) \(=\dfrac{5392+\left(600+1\right)x5391}{5392x\left(600+1\right)-69}=\dfrac{5392+600x5391+5391}{5392x600+5392-69}\)
\(=\dfrac{10783+3234600}{3235200+5323}=\dfrac{\text{3245383}}{\text{3240523}}=\dfrac{3240523+60}{3240523}=1+\dfrac{60}{3240523}\)
c) \(=\dfrac{1}{2}x\left(\dfrac{1}{2}-\dfrac{1}{4}\right)+\dfrac{1}{2}x\left(\dfrac{1}{4}-\dfrac{1}{8}\right)+\dfrac{1}{32}\)
\(=\dfrac{1}{2}x\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{8}\right)+\dfrac{1}{32}\)
\(=\dfrac{1}{2}x\left(\dfrac{1}{2}-\dfrac{1}{8}\right)+\dfrac{1}{32}=\dfrac{3}{16}+\dfrac{1}{32}=\dfrac{7}{32}\)
1) So sánh phân số:
23/27 và 22/29
12/25 và 25/49
2) Tính nhanh
254 x 399 - 145/254 + 399 x 253
5932+6001 x 5931/5932 x 6001 - 69
Rất mong các bn giúp đỡ! Cảm ơn rất nhiều!
tính nhanh A = 254 * 399 - 145 / 254 + 399 * 254
B = 5932+6001*5931 / 5932*6001-69
C = ( 1-1/2) * (1-1/3) * ... * ( 1-1/2017 )
C=\(\frac{1}{2}.\frac{2}{3}.......\frac{2016}{2017}\)
C= CÂU HỎI TƯƠNG TỰ
=> đcpm
\(A=\frac{254\cdot399-145}{254+399\cdot253}\)
\(A=\frac{\left(253+1\right)\cdot399-145}{254+399\cdot253}\)
\(A=\frac{253\cdot399+\left(399-145\right)}{254+399\cdot253}\)
\(A=\frac{253\cdot399+254}{254+399\cdot253}\)
\(A=1\)
\(B=\frac{5932+6001\cdot5931}{5932\cdot6001-69}\)
\(B=\frac{5932+6001\cdot5931}{\left(5931+1\right)\cdot6001-69}\)
\(B=\frac{5932+6001\cdot5931}{5931\cdot6001+\left(6001-69\right)}\)
\(B=\frac{5932+6001\cdot5931}{5931\cdot6001+5932}\)
\(B=1\)
\(C=\left(1-\frac{1}{2}\right)\cdot\left(1-\frac{1}{3}\right)\cdot...\cdot\left(1-\frac{1}{2017}\right)\)
\(C=\frac{1}{2}\cdot\frac{2}{3}\cdot...\cdot\frac{2016}{2017}\)
\(C=\frac{1\cdot2\cdot3\cdot...\cdot2016}{2\cdot3\cdot4\cdot...\cdot2017}\)
\(C=\frac{1}{2017}\)
Tính nhanh
a,254 x 399 - 145/ 254 + 399 x 253
b,5932 + 6001 x 5931 / 5932 x 6001 - 69
Tính nhanh:
a) \(\frac{254.399-145}{254+399.253}\)
\(=\)\(\frac{\left(253+1\right).399-145}{254+399.253}\)
\(=\)\(\frac{253.399+399-145}{254+399.253}\)
\(=\)\(\frac{253.399+254}{254+399.253}\)
\(=\)\(1\)
b) \(\frac{5932+6001.5931}{5932.6001-69}\)
\(=\)\(\frac{5932+6001.5931}{\left(5931+1\right).6001-69}\)
\(=\)\(\frac{5932+6001.5931}{5931.6001+6001-69}\)
\(=\)\(\frac{5932+6001.5931}{5932.6001+5932}\)
\(=\)\(1\)
a, 254 x 399 - 145/254 + 399 x 253
b, 5932 + 6001 x 5931/5932 x 6001 - 69
Các bạn hãy giúp mình giải 2 bài toán sau nhé:
a)254 x 399 - 145 / 254 + 399 x 253
b)5932 + 6001 x 5931 / 5932 x 6001 - 69
Bài 1. Tính nhanh :
a) 254 x 399 - 145 / 254 + 399 - 253 b) 5932 + 6001 x 5931 c) B = ( 1 - 1/2 ) x ( 1 - 1/3 ) x ( 1 - 1/4 ) x . . . . . x ( 1/2002 )
Bài 2. Tìm X :
a) X x 1 1/4 = 3 3/4 ( Hỗn số ) b) X - 3/4 = 6 x 3/8 c) 3/2 x 4/5 - X = 2/3 g) 49/8 : X = 49/5 d) X x 3 1/3 = 3 1/3 : 4 1/4 ( Hỗn số ) e) 5 2/3 : X = 3 2/3 - 2 1/2 ( Hỗn số ) g) 49/8 : X = 49/5 h) 648 - 34x X = 444
Giải nhanh giúp mk nha mn , mk cần gấp ngay trong hnay ! Mơn mn nhiều .
Bài 2
a) \(x\times1\frac{1}{4}=3\frac{3}{4}\)
\(x\times\frac{5}{4}=\frac{15}{4}\)
\(x=\frac{15}{4}.\frac{4}{5}\)
\(x=3\)
b) \(x-\frac{3}{4}=6\times\frac{3}{8}\)
\(x-\frac{3}{4}=\frac{9}{4}\)
\(x=\frac{9}{4}+\frac{3}{4}\)
\(x=3\)
Những câu còn lại tương tự
tính nhanh:
A,\(\frac{254x399-145}{254+399\text{x}253}\)B,\(\frac{5932+6001\text{x}5931}{5931\text{x}6001-69}\)
ai xong cho 3 tích và đúng, chữ x là dấu nhân nhé!
#)Giải :
A, \(\frac{254x399-145}{254+399x253}\)
\(=\frac{253x399+399-145}{254+399x253}\)
\(=\frac{253x399+254}{254+399x253}\)
\(=1\)
B, \(\frac{5932+6001x5931}{5931x6001-69}\)
\(=\frac{5932+6001x5931}{\left(5931+1\right)x6001-69}\)
\(=\frac{5932+6001x5931}{5931x6001+6001-69}\)
\(=\frac{5932+6001x5932}{5932x6001+5932}\)
\(=1\)
#~Will~be~Pens~#
\(\frac{254x399-145}{254+399x253}=\frac{\left(253+1\right)x399-145}{254+399x253}=\frac{253x399+1x399-145}{254+399x253}=\frac{253x399+254}{254+399x253}\)
\(=1\)
\(\frac{254x399-145}{254+399x253}\)
=\(\frac{\left(253+1\right)x399-145}{254+399x253}\)
=\(\frac{253x399+399-145}{254+399x253}\)
=\(\frac{253.399+254}{254+399x253}\)=\(1\)
\(\frac{5932+6001x5931}{5931x6001-69}\)
=\(\frac{5932+6001x5931}{\left(5931+1\right)x6001-69}\)
=\(\frac{5932+6001x5931}{5931x6001+6001-69}\)
=\(\frac{5932+6001x5931}{5931x6001x5932}\)=1
# Hok tốt
Tính nhanh
254x399-145 / 254+399 x 255
5932+6001x5931 / 5932x6001-69
Câu a sai đề (sửa đề lại rồi làm tương tự câu b
Câu b
\(\frac{5932+6001\times5931}{5932\times6001-69}=\frac{5932+6001\times5931}{\left(5931+1\right)\times6001-69}=\frac{5932+6001\times5931}{5931\times6001+6001-69}=\frac{5932+6001\times5931}{5932\times6001+5932}=1\)
\(254.399-\frac{145}{254+399.255}=101346-\frac{145}{101999}=1012031170\)
\(5932+6001.\frac{5931}{35597863}=1\)