Bài 3: Trang 178 - sách giáo khoa (SGK) toán tiếng Anhlớp 4Calculate:Tính:a) \({2 \over 5} + {1...

{
"content1": "a) \({2 \over 5} + {1 \over 2} + {7 \over {10}}\) = \({4 \over 10} + {5 \over 10} + {7 \over {10}}\) = \({16 \over 10} = {8 \over 5} = 1.6\)",
"content2": "b) \({4 \over 9} + {{11} \over 8} - {5 \over 6}\) = \({32 \over 72} + {99 \over 72} - {60 \over 72}\) = \({71 \over 72}\)",
"content3": "c) \({9 \over {20}} - {8 \over {15}} \times {5 \over {12}}\) = \({9 \over {20}} - {4 \over 3} \times {5 \over {12}} = {9 \over {20}} - {20 \over 36} = {9 \over {20}} - {5 \over 9} = {27 \over {60}} - {50 \over 60} = -{23 \over 60}\)",
"content4": "d) \({2 \over 3}:{4 \over 5}:{7 \over {12}}\) = \({2 \over 3} \times {5 \over 4} \times {12 \over 7} = {10 \over 12} = {5 \over 6}\"
}