Suma

[ROBINDESBOIS]

How do we say la suma de ambos when we talk about the time we spend on cooking, if we want to say all told la suma de ambos , lunch and dinner I spend 70 minutes.

[Perikles]

I spend a total of 70 minutes on cooking lunch and dinner
In total, I spend 70 minutes ....

[poli]

You can even use the direct translation
I spend a sum of 60 minutes ....

[ROBINDESBOIS]

y para restar como se dice? Por ejemplo
Para restar el tiempo que paso en la cama, paso menos tiempo cocinando.

[poli]

To leave me more time in bed...

(although I have never heard restar used before. I would use dejar.)

[ROBINDESBOIS]

I don´t know it maybe contrarestar.