bài 1 tính nhanha) 3\(\frac{1}{417}\). \(\frac{1}{762}\)-\(\frac{1}{139}\).\(4\frac{761}{762}\)-\(\frac{4}{417.762}\)+\(\frac{5}{139}\)b) \(5\frac{4}{23}\). \(27\frac{3}{27}\)+ \(4\frac{8}{27}\).\(-5\frac{4}{23}\)c) \(3\frac{10}{99}\). \(6\frac{1}{4}\)+ \(3\frac{2}{5}\).\(3\frac{3}{4}\)bài 2 tính tổngS=...
Đọc tiếp
bài 1 tính nhanh
a) 3\(\frac{1}{417}\). \(\frac{1}{762}\)-\(\frac{1}{139}\).\(4\frac{761}{762}\)-\(\frac{4}{417.762}\)+\(\frac{5}{139}\)
b) \(5\frac{4}{23}\). \(27\frac{3}{27}\)+ \(4\frac{8}{27}\).\(-5\frac{4}{23}\)
c) \(3\frac{10}{99}\). \(6\frac{1}{4}\)+ \(3\frac{2}{5}\).\(3\frac{3}{4}\)
bài 2 tính tổng
S= 1+2+5+14+...+ \(\frac{3^n+1}{2}\)
