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) \(\frac{5932+6001.5931}{5932.6001-69}\)
\(=\)\(\frac{5932+6001.5931}{\left(5931+1\right).6001-69}\)
\(=\)\(\frac{5932+6001.5931}{5931.6001+6001-69}\)
\(=\)\(\frac{5932+6001.5931}{5932.6001+5932}\)
\(=\)\(1\)