Tính rồi rút gọn:
a) \(\displaystyle{8 \over {15}} + {2 \over 3}\) b) \(\displaystyle{3 \over 7} + {4 \over 8}\)
a) \(\displaystyle{8 \over {15}} + {2 \over 3} = {8 \over {15}} + {{10} \over {15}} = {{18} \over {15}} = {6 \over 5}\)
b) \(\displaystyle{3 \over 7} + {4 \over 8} = {{24} \over {56}} + {{28} \over {56}} = {{52} \over {56}} = {{13} \over {14}}\)
-- Mod Toán lớp 4