Question

Calculați:
a) 42/14 - 20/9 + 1/12
b) 5/24 + 32/128 - 11/90
c) 1/42 + 8/735 - 1/49 ​

Answer 1

Răspuns:

Explicație pas cu pas:

a) 42/14 - 20/9 + 1/12 = 3 - 20/9 + 1/12 =

= (108-80+3)/36 = 31/36

b) 5/24 + 32/128 - 11/90 = 5/24 + 1/4 - 11/90 =

= (75+90-44)/360 = 121/360

c) 1/42 + 8/735 - 1/49 = (35+16-30)/1470 =

= 21/1470 = 1/70

Answer 2

Răspuns:

$a) \frac{42}{ 14} - \frac{20}{9} + \frac{1}{12} = \frac{3}{1} - \frac{20}{9} + \frac{1}{12} = \frac{3}{1} - \frac{20 \times 4}{9 \times 4} + \frac{1 \times 3}{12 \times 3} = \frac{3 \times 36}{1 \times 36} - \frac{20 \times 4}{9 \times 4} + \frac{1 \times 3}{12 \times 3} = \frac{108}{36} - \frac{80}{36} + \frac{3}{36} = \frac{108 - 80 + 3}{36} = \frac{31}{36} \\ \\ b) \frac{5}{24} + \frac{32}{128} - \frac{11}{90} = \frac{5}{24} + \frac{1}{4} - \frac{11}{90} = \frac{5 \times 15}{24 \times 15} + \frac{1 \times 90}{4 \times 90} - \frac{11 \times 4}{90 \times 4} = \frac{75 + 90 - 44}{360} = \frac{121}{360} \\ \\ c) \frac{1}{42} + \frac{8}{735} - \frac{1}{49} = \frac{35}{1470} + \frac{16}{1470} - \frac{30}{1470} = \frac{35 + 16 - 30}{1470} = \frac{21}{1470} = \frac{1}{70}$