Tính:
a) \(\displaystyle{8 \over 9} - {1 \over 3}\) b) \(\displaystyle{4 \over 5} - {6 \over {25}}\)
a) \(\displaystyle{8 \over 9} - {1 \over 3} = {{24} \over {27}} - {9 \over {27}} = {{15} \over {27}} = {5 \over 9}\)
b) \(\displaystyle{4 \over 5} - {6 \over {25}} = {{20} \over {25}} - {6 \over {25}}= {{14} \over {25}}\)
-- Mod Toán lớp 4