Question

Calculați grupând convenabil termenii . 1/5 + 14/15+9/14+5/84/+49/75

Answer 1

$\frac{1}{5} + \frac{14}{15} + \frac{49}{75} + \frac{9}{14} +\frac{5}{84} =$
Aducem la acelasi numitor primii trei membrii cu numitorul 75 , iar urmatorii cu numitorul 84

$\frac{15*1}{15*5}+\frac{5*14}{5*15}+\frac{49}{75}+\frac{6*9}{6*14}+\frac{5}{84}$=

$\frac{15}{75}+\frac{70}{75}+\frac{49}{75}+\frac{54}{84}+\frac{5}{84}=\frac{15+70+49}{75}+\frac{54+5}{84}=\frac{134}{75}+\frac{59}{84}=$
Aducem la acelasi numitor prima fractie o inmultim cu 28 a doua cu 25

$\frac{134*28}{75*28} + \frac{59*25}{84*25}= \frac{134*28+59*25}{2100} = \frac{3752+1475}{2100}= \frac{5227}{2100}$