Question

efetue as operações com as frações:
A) 3/10 + 2/5=

B) 3/8 + 5/12=

C) 10/12 - 2/3=

D) 2/15 - 5/12=

E) 2/3 + 4/10 + 1/5=

F) 1/3 + 5/12 + 10/15=

G) 2/3 + 4/5=

H) 4/5 - 2/3=

I) 6/9 - 4/12=

me ajudem

J) 8/3 + 5/4=
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Answer 1

quando os denominadores são diferentes temos que fatorar eles para deixar iguais e deixar como denominador e dps só fazer a soma dos numeradores
_______________

A) 3/10 + 2/5= 5/10

mmc
10, 5 | 5
2, 1 | 2
1, 1 | 5.2= 10
_______________

B) 3/8 + 5/12= 8/24

mmc
8, 12 | 2
4, 6 | 2
2, 3 | 2
1, 3 | 3
1, 1 | 2.2.2.3=24
_______________

C) 10/12 - 2/3= 8/12

mmc
12, 3 | 2
6, 3 | 2
3, 3 | 3
1, 1 | 2.2.3= 12
_______________

D) 2/15 - 5/12= -3/60

mmc
15, 12 | 2
15, 6 | 2
15, 3 | 3
5, 1 | 5
1, 1 | 2.2.3.5= 60
___________________

E) 2/3 + 4/10 + 1/5= 7/30

mmc
3, 10, 5 | 2
3, 5, 5 | 3
1, 5, 5 | 5
1, 1, 1 | 2.3.5=30
____________________

F) 1/3 + 5/12 + 10/15= 16/60

mmc
3, 12, 15 | 2
3, 6, 15 | 2
3, 3, 15 | 3
1, 1, 5 | 5
1, 1, 1 | 2.2.3.5=60
____________________

G) 2/3 + 4/5= 6/15

mmc
3, 5 | 3
1, 5 | 5
1, 1 | 3.5= 15
_______________

H) 4/5 - 2/3= 2/15

mmc
5, 3 | 3
5, 1 | 5
1, 1 | 3.5=15
______________

I) 6/9 - 4/12= 2/36

mmc
9, 12 | 2
9, 6 | 2
9, 3 | 3
3, 1 | 3
1, 1 | 2.2.3.3=36
_______________

J) 8/3 + 5/4= 13/12

mmc
3, 4 | 2
3, 2 | 2
3, 1 | 3
1, 1 | 2.2.3= 12
______________

espero que dê para entender :)