1 Tính nhanh a ; 5\(\frac{2}{3}\) x 7\(\frac{7}{12}\) x 13\(\frac{8}{9}\) x 7\(\frac{5}{13}\)b; \(\frac{5}{6}\)x \(\frac{4}{19}\) + \(\frac{7}{12}\) x \(\frac{4}{19}\) + \(\frac{40}{57}\)c; \(\frac{3}{7}\)x \(\frac{9}{26}\) - \(\frac{1}{14}\) x 1\(\frac{1}{13}\)2 tìm x ,...
Đọc tiếp
1 Tính nhanh
a ; 5\(\frac{2}{3}\) x 7\(\frac{7}{12}\) x 13\(\frac{8}{9}\) x 7\(\frac{5}{13}\)
b; \(\frac{5}{6}\)x \(\frac{4}{19}\) + \(\frac{7}{12}\) x \(\frac{4}{19}\) + \(\frac{40}{57}\)
c; \(\frac{3}{7}\)x \(\frac{9}{26}\) - \(\frac{1}{14}\) x 1\(\frac{1}{13}\)
2 tìm x , biết
\(\frac{5}{17}\)+ \(\frac{4}{9}\)+ \(\frac{20}{31}\)+ \(\frac{12}{17}\)+ \(\frac{11}{31}\)< \(\frac{x}{9}\)\(\le\)\(\frac{3}{7}\)+ \(\frac{7}{15}\)+ \(\frac{4}{7}\)+ \(\frac{8}{15}\)+ \(\frac{2}{3}\)
