Tính nhanh :
254 . 399 - 145
254+399x253
tính nhanh
254x399-145
___________
254+399x253
A = \(\dfrac{254\times399-145}{254+399\times253}\)
A = \(\dfrac{\left(253+1\right)\times399-145}{254+399\times253}\)
A = \(\dfrac{253\times399+399-145}{254+399\times253}\)
A = \(\dfrac{253\times399+254}{254+399\times253}\)
A = 1
a) \(254x399-145=\left(250+4\right)\left(400-1\right)-145\)
\(=100000+1600-250-145-4=101600-\left(250+145+4\right)\)
\(=101600-399=101201\)
b) \(254+399x253=254+\left(400-1\right)x\left(250+3\right)\)
\(=254+100000+1200-250-3\)
\(=101454-250-3=101201\)
Tính nhanh:254*399-145/254+399*253=?
b2 tính nhanh
254x399-145 / 254+399x253
\(\frac{254.399-145}{254+399.253}\)
\(=\frac{253.399+399-145}{254+399.253}\)
\(=\frac{253.399+254}{254+399.253}=1\)
Trả lời
254.399-145/254+399.253
=253.399+399-145/254+399.253
=253.399+254/254+399.253
=1.
254x399-145/254+399x253 các bạn tính nhanh cho mình nha
= 202292,42913385826771653543307087.............
=202292,4291338582677165353307087
bài 1 tính nhanh
254 x 399 - 145 / 254 + 399 x 253
\(\frac{254.399-145}{254+399.253}=\frac{\left(253+1\right).399-145}{254+399.253}=\frac{253.399+399-145}{254+399.253}=\frac{253.399+254}{254+399.253}=1\)
bài 1 tính nhanh
254 x 399 - 145 / 254 + 399 x 253
ghép đầu cuối dăt chung 399 ra ngoài
kq vẫn như cũ chắc chắn 100%
202292.4291
Tính nhanh :
254 + 399 x 253 / 399 x 254 - 145
dấu / là phần
\(\frac{254+399.253}{399.254-145}\)
\(=\frac{254+399.253}{399.\left(253+1\right)-145}\)
\(=\frac{254+399.253}{399.253+399.1-145}\)
\(=\frac{254+1}{1+399-145}=1\)
Chúc bạn học tốt!!!
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:
\(\frac{254x399-145}{254+399x253}\)