\(\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+...+\frac{1}{38\cdot39}+\frac{1}{39.40}\)
\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{38}-\frac{1}{39}+\frac{1}{39}-\frac{1}{40}\)
\(\frac{1}{2}-\frac{1}{40}\)
= 0,475
Calculate:
\(1+\frac{1}{1+2}+\frac{1}{1+2+3}+...+\frac{1}{1+2+3+...+19}=...\)
(Write your answer by fraction in the simpliest form)
Question 3: 51 hours = ............ days. (Write your answer by decimal in the simplest form)
Question 3: 51 hours = ............ days. (Write your answer by decimal in the simplest form)
Tính A = \(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+......+\frac{1}{99.100}=?\)
Question 2: 12 hours 24 minutes x 2 = ............. hours. (Write your answer by decimal in the simplest form)
Question 2: 12 hours 24 minutes x 2 = ............. hours. (Write your answer by decimal in the simplest form)
\(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+......+\frac{1}{380}\)= ?
1/2x3 + 1/3x4 +1/4x5+ ....+ 1/380 = ?
Bài 1. Tính nhanh nếu có thể:
A = 1 + 2 + 3 + 4 + 5 + ... + 99 + 100
B = \(\frac{1}{1.2}\)+ \(\frac{1}{2.3}\)+\(\frac{1}{3.4}\)+\(\frac{1}{4.5}\)+\(\frac{1}{5.6}\)+ ... +\(\frac{1}{99.100}\)
Tính\(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{18.19}+\frac{1}{19.20}\)
