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1. >; <; =
\(\eqalign{
& 5{1 \over 7}……….2{6 \over 7}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,3{2 \over 7}………3{5 \over 7} \cr
& 8{6 \over {10}}……….8{3 \over 5}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,9{1 \over 2}………5{1 \over 2} \cr} \)
2. Chuyển các hỗn số sau thành phân số rồi thực hiện phép tính
a) \(2{1 \over 8} + 1{3 \over 4} = ……………….\)
\(3{2 \over 7} + 1{3 \over 7} = ………………..\)
b) \(5{1 \over 3} – 2{5 \over 6} = ……………….\)
\(4{7 \over 9} – 1{5 \over 9} = ……………\)
c) \(2{4 \over 5} \times 3{1 \over 8} = …………….\)
\(1{1 \over 5}:1{4 \over 5} = ……………\)
3. Tính
\({{9 \times 42} \over {14 \times 27}} = ………………….\)
Đáp án
1. >; <; =
\(\eqalign{
& 5{1 \over 7}\,\, > 2{6 \over 7}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,3{2 \over 7}\, < \,3{5 \over 7} \cr
& 8{6 \over {10}}\, = \,8{3 \over 5}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,9{1 \over 2}\, > \,5{1 \over 2} \cr} \)
2. Chuyển các hỗn số sau thành phân số rồi thực hiện phép tính
a)
\(2{1 \over 8} + 1{3 \over 4} = {{17} \over 8} + {7 \over 4} = {{17} \over 8} + {{14} \over 8} = {{17 + 14} \over 8} = {{31} \over 8}\)
\(3{2 \over 7} + 1{3 \over 7} = {{23} \over 7} + {{10} \over 7} = {{23 + 10} \over 7} = {{33} \over 7}\)
b)
\(5{1 \over 3} – 2{5 \over 6} = {{16} \over 3} – {{17} \over 6} = {{32} \over 6} – {{17} \over 6} = {{32 – 17} \over 6} = {{15} \over 6} = {5 \over 2}\)
\(4{7 \over 9} – 1{5 \over 9} = {{43} \over 9} – {{14} \over 9} = {{43 – 14} \over 9} = {{29} \over 9}\)
c)
\(2{4 \over 5} \times 3{1 \over 8} = {{14} \over 5} \times {{25} \over 8} = {{14 \times 25} \over {5 \times 8}} = {{350} \over {40}} = {{35} \over 4}\)
\(1{1 \over 5}:1{4 \over 5} = {6 \over 5}:{9 \over 5} = {6 \over 5} \times {5 \over 9} = {2 \over 3}\)
3. Tính
\({{9 \times 42} \over {14 \times 27}} = {{9 \times 3 \times 14} \over {14 \times 3 \times 9}} = 1\)