Rút hơn rồi tính: a) 8/36 + 4/9 b) 18/15 + 4/30 c)2/3 + 6/9 d) 6/12 + 3/2

a) `8/36 + 4/9`

`= (8:4)/(36:4) + 4/9`

`= 2/9 + 4/9`

`= 6/9`

`= 2/3`

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b) `18/15 + 4/30`

`= 18/15 + (4:2)/(30:2)`

`= 18/15 + 2/15`

`= 20/15`

`= 4/3`

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c) `2/3 + 6/9`

`= 2/3 + (6:3)/(9:3)`

`= 2/3 + 2/3`

`= 4/3`

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d) `6/12 + 3/2`

`= (6:6)/(12:6) + 3/2`

`= 1/2 + 3/2`

`= 4/2`

`= 2`