3/5 + 1/4=12+5/20=17/20.
giúp em với ạ
gúp mik
1) tính. (1đỉm)
a) 6/17 + 13/17 b) 5 x 8/20a)\(\dfrac{3}{5}\)+\(\dfrac{17}{21}\)*\(\dfrac{17}{21}\)+\(\dfrac{3}{5}\)
b)\(\dfrac{15}{8}\):\(\dfrac{5}{20}\)-\(\dfrac{7}{8}\):\(\dfrac{1}{4}\)
1) Tính thuận tiện
a) 3×17-5×3-2×3
b) 17×7+2×17+17
c) 240:122
d) 5268+803+197+4732
e) 4×5×25×20
20-19+18-17+...+5-4+3-2+1
1+2+3+4+5...+15+16+17+18+19+20
1+2+3+4+5+6+..........+16+17+18+19+20
câu 6 : tính a) 3/5 + 1/3 b) 17/20 - 4/5 c) 25/35 x 4/5 d) 7/15 : 6/7
Tính nhanh
a ) 6/9 + 5/7 +1/3
b ) 17/7 + 6/5 - 20 / 14
c ) 1/2 + 1/6 +1/12 + 1/72
Tính nhanh
19 + 18 + 17 + 16 + 14 + 21 + 22 + 23 + 24 + 25 + 26
1/3 + 1/4 + 1/5 + 4/6 + 9/12 + 16/20