Question

calcular o valor das expressões numéricas, lembrando a ordem das operações:
a) 3/11 × (1/5 + 2)=
b) ( 2 1/4 - 3/8) × (5/12 + 1/4)=

Answer 1

$a) \\ \frac{3}{11} \times( \frac{1}{5} +2)= \\ \\ \frac{3}{11} \times( \frac{1+10}{2} )= \\ \\ \frac{3}{\not11} \times \frac{\not11}{2} = \frac{3}{2} =1 \frac{1}{2} \\ \\ \\ b) \\ (2 \frac{1}{4} - \frac{3}{8} )\times( \frac{5}{12} + \frac{1}{4} )= \\ \\ ( \frac{9}{4} - \frac{3}{8} )\times( \frac{5+3}{12} )= \\ \\ ( \frac{18-3}{8} )\times \frac{8}{12} = \\ \\ \frac{15}{\not8} \times \frac{\not8}{12} = \frac{15}{12} = \frac{5}{4} =1 \frac{1}{4}$