Question

Efetue as operações indicadas: 

d) 2 1/2 - 3/5
e)2 3/5-3/10
f)8+1/3-3/4

Answer 1

E aí mano,

transforme as frações mistas em fração imprópria, em seguida tire o MMC se necessário:


$2 \dfrac{1}{2}- \dfrac{3}{5}~~\to~~\dfrac{2*2+1}{2}- \dfrac{3}{5}~~\to~~ \dfrac{4+1}{2}- \dfrac{3}{5}~~\to~~ \dfrac{5}{2}- \dfrac{3}{5}\\\\ MMC(2,5)=10:\\\\ \dfrac{5*5-2*3}{10}~~\to~~ \dfrac{25-6}{10}~~\to~~ \dfrac{19}{10}$

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$2 \dfrac{3}{5}- \dfrac{3}{10}~~\to~~ \dfrac{2*5+3}{5}- \dfrac{3}{10}~~\to~~ \dfrac{15+3}{5}- \dfrac{3}{10}~~\to~~ \dfrac{18}{5}- \dfrac{3}{10}\\\\ MMC(5,10)=10\\\\ \dfrac{2*18-1*3}{10}~~\to~~ \dfrac{36-3}{10}~~\to~~ \dfrac{33}{10}$

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$8+ \dfrac{1}{3}- \dfrac{3}{4}~~\to~~ \dfrac{8*3+1}{3}- \dfrac{3}{4}~~\to~~ \dfrac{24+1}{3}- \dfrac{3}{4}~~\to~~ \dfrac{25}{3}- \dfrac{3}{4}\\\\ MMC(3,4)=12\\\\ \dfrac{4*25-3*3}{12}~~\to~~ \dfrac{100-9}{12}~~\to~~ \dfrac{81}{12}= \dfrac{81:3}{12:3}= \dfrac{27}{4}$

Espero ter ajudado e tenha ótimos estudos =))