tính nhanh
d) \(\frac{254x399-145}{254x399x253}\)
tính nhanh
\(\frac{254x399-145}{254+399x255}\)
\(\frac{254x399-145}{254+399x\left(254+1\right)}\)
\(=\frac{254x399-145}{254+399x254+399}\)
\(=\frac{-145}{254+399}\)
\(=\frac{-145}{653}\)
Tính nhanh:
\(\frac{254x399-145}{254+399x253}\)
Tính nhanh:
\(\frac{254x399-145}{254+399x253}\)
254 × 399 - 145 / 254 + 399 × 253
= (253 + 1) × 399 - 145 / 254 + 399 × 253
= 253 × 399 + (399 - 145) / 254 + 399 × 253
= 253 × 399 + 254 / 254 + 399 × 253
= 1
\(\frac{254x399-145}{254+399x253}\)
\(=\frac{253x399+399-145}{254+399x253}\)
\(=\frac{253x399+254}{254+399x253}=1\)
\(\frac{254.399-145}{254+399.253}=\frac{254.399-145}{\left(254-1\right).399+254}\)\(=\frac{254.399-145}{254.399-399+254}=\frac{254.399-145}{254.399-145}=1\)
DẤU . LÀ DẤU NHÂN NHA
tính nhanh
a.\(\frac{254x399-145}{254+399x253}\)
b. \(\frac{5932x6001x5931}{5932x6001-69}\)
a) \(\frac{254.399-145}{254+399.253}\)
\(=\frac{253.399+399-145}{254+399.253}\)
\(=\frac{253.399+254}{254+399.253}\)
\(=1\)
b) tự làm
\(\frac{254x399-145}{254+399x253}\)
\(\frac{254.399-145}{254+399.253}=\frac{\left(253+1\right).399-145}{254+399.253}=\frac{253.399+\left(399-145\right)}{254+399.253}\)
\(=\frac{253.399+254}{254+399.253}=1\)
\(\frac{254\times399-145}{254+399\times253}\)
\(=\frac{253\times399+399-145}{254+399\times253}\)
\(=\frac{253\times399+254}{254+399\times253}\)
\(=1\)
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) \(254+399x253=254+\left(400-1\right)x\left(250+3\right)\)
\(=254+100000+1200-250-3\)
\(=101454-250-3=101201\)
\(\frac{254X399-145}{254+399X253}\)
(253+1)x399-145/254+399x253
=253x399+(399-145)/254+399x253
=253x399+254/254+399x253
=1
Ta có:
\(\frac{254X399-145}{254+399X253}\)
\(=\frac{\left(253+1\right)X399-154}{254+399X253}\)
\(=\frac{253X399+399-154}{254+399X253}\)
\(=\frac{253X399+254}{253X399+254}\)
\(=1\)
\(\frac{254x399-145}{254+399x255}\)
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
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.