Question

1so sánh: \(\frac{1}{5}\)-\(\frac{1}{6}\) với\(\frac{1}{5.6}\)

\(\frac{1}{6}\) - \(\frac{1}{7}\)với \(\frac{1}{6.7}\)

2. Tính nhanh

\(\frac{1}{1.2}\)+ \(\frac{1}{2.3}\)+ \(\frac{1}{3.4}\)+\(\frac{1}{4.5}\) + \(\frac{1}{5.6}\)

Nhanh nhanh mai em nộp

Answer 1

1) \(\frac{1}{5}-\frac{1}{6}=\frac{6-5}{5.6}=\frac{1}{5.6}\)

\(\frac{1}{6}-\frac{1}{7}=\frac{7-6}{6.7}=\frac{1}{6.7}\)

2) Áp dụng bài trên, ta có:

\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}\)

= \(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\)

= \(1-\frac{1}{6}=\frac{5}{6}\)