399+254x399-399x255/399x255+399x255
399+254x399-399x255/399x254+399x255
ai đúng ,nhanh và tick cho tớ,tớ tick cho
399 + 254 x 399 - 399 x 255 : 399 x 254 + 399 x 255
1 x 399 + 254 x 399 - 399 x 255 : 399 x 254 + 399 x 255
( 1 + 254 - 255 ) x 399 : 399 x ( 254 + 255 )
0 x 399 x A
0
\(\frac{254\times399-145}{254+399\times253}=\frac{'253+1'\times399-145}{254+399\times253}\)
\(=\frac{235\times399-145}{254+399\times253}\)
\(=\frac{253\times399+254}{254+399\times253}\)
\(=1\)
Vậy: Số cần tìm là :1
=399x1+254x399-399x255/399x254+399x255
=399x(254+1-255)/399x(254+255)
=399x0/399x509=0
tính nhanh
\(\frac{254x399-145}{254+399x255}\)
\(\frac{254x399-145}{254+399x\left(254+1\right)}\)
\(=\frac{254x399-145}{254+399x254+399}\)
\(=\frac{-145}{254+399}\)
\(=\frac{-145}{653}\)
\(\frac{254x399-145}{254+399x255}\)
giúp mình nhá
254 x399 - 145 / 254 + 399 x 255
= ( 253 + 1 ) x 399 - 145 / 254 + 399 x 255
= 253 x 399 + ( 399 - 145 )/ 254 + 399 x 255
= 254 x 399 + 255 / 254 + 399 x 155
= 1
\(\frac{256+399x255}{256x399-143}\)
tính
256 + 399x255/256x399-143
= 256+399x255/(255+1)x399-143
=256+399x255/255x399+399-143
=256+399x255/255x399+256
=1
tinh bang cach hop li 256+399x255
256x399-143
256+399x255
256x399-143
nếu A bằng phân số đó thì A bằng bao nhiêu
Trả lời: A = .............
Tính
\(A=\frac{99x98+100}{100x99-98}\) ; \(B=\frac{256+399x255}{256x399-143}\)
A = 99x98+100
100x99-98
= 99 x 98 +100
98x99+99+99-98
= 99x98 +100
98x99 + 99+1
= 98x99+100
98x99+100
= 1
Câu B tương tự
tính nâng cao
1) \(\left(1-\frac{1}{2}\right)x\left(1-\frac{1}{3}\right)x\left(1-\frac{1}{4}\right).............\)
2) \(5\frac{9}{10}:\frac{3}{2}-\left(2\frac{1}{3}x4\frac{1}{2}-2x2\frac{1}{3}\right):\frac{7}{4}\)
3) \(254x399-145\)
4) \(254+399x255\)
5) \(638+780x5-369:9\)
6) \(\left(275+485\right)x16-483:3x4\)
7 ) \(\frac{13}{15}+\frac{4}{7}-\frac{101}{105}\)
2: \(=\dfrac{59}{10}\cdot\dfrac{2}{3}-\left[\dfrac{7}{3}\cdot\left(4+\dfrac{1}{2}-2\right)\right]\cdot\dfrac{4}{7}\)
\(=\dfrac{59}{15}-\dfrac{4}{3}\cdot\dfrac{5}{2}=\dfrac{59}{15}-\dfrac{10}{3}=\dfrac{59-50}{15}=\dfrac{9}{15}=\dfrac{3}{5}\)
4: \(=254+254\cdot399+399\)
\(=254\cdot400+399\)
\(=101600+399=101999\)
5: \(=638+3900-41=3900+597=4497\)
A= 254x399–145 / 254+399 x 253=
\(\frac{254.399-145}{254+399.253}=\frac{253.399+399-145}{253.399+254}=\frac{253.399+254}{253.399+254}=1\)