How to Say "i deduct" in Spanish
The Spanish word for “i deduct” is “resto” — B1 level.

Examples
Si resto veinte de cincuenta, me quedan treinta.
If I subtract twenty from fifty, I have thirty left.
Cada mes, resto los gastos de mi sueldo para ver cuánto puedo ahorrar.
Every month, I subtract the expenses from my salary to see how much I can save.
The Other Meaning of 'Restar'
Besides subtracting, 'restar' can also mean 'to remain' or 'to be left', similar to 'quedar'. For example: 'Solo resta esperar' means 'All that's left is to wait'.
Confusing 'restar' with 'quedar'
Mistake: “Restan tres manzanas.”
Correction: While technically understandable, it's much more natural to say 'Quedan tres manzanas' (There are three apples left). Use 'quedar' to talk about what remains and 'restar' for the action of subtracting.
Related Translations
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