a) \(1{5 \over 7} \times {3 \over 4} = {{12} \over 7} \times {3 \over 4} = {{12 \times 3} \over {7 \times 4}} = {{3 \times 4 \times 3} \over {7 \times 4}} = {9 \over 7}\)
b) \({{10} \over {11}}:1{1 \over 3} = {{10} \over {11}}:{4 \over 3} = {{10} \over {11}} \times {3 \over 4} = {{10 \times 3 } \over {11 \times 4}} = {{5 \times 2 \times 3 } \over {11 \times 2 \times 2}} = {{15} \over {22}}\)
c) 3,75 x 4,1 + 2,43 x 4,1 = (3,75 + 2,43) x 4,1
= 6 x 4,1
= 24,6
d) 3,42 : 0,57 x 8,4 - 6,8 = 6 x 8,4 - 6, 8
= 50,4 - 6,8
= 43,6