To deduce means to think carefully and find the answer from facts. You use what you know and find out something new by reasoning.
I deduce the answer from the clues.
She deduced he was late from his silence.
Deduce can mean to take away or subtract money or value. For example, money is taken away from a total amount for taxes or costs.
They deduce tax from your salary.
We deduce costs before paying bills.
To deduce means to find out details by careful study of facts or evidence. It is often used in science and investigation.
Scientists deduce facts from data.
Detectives deduce who did the crime.
In math and logic, to deduce means to find a result by using correct steps from basic truths or rules. It is formal and exact reasoning.
Mathematicians deduce formulas from axioms.
Logicians deduce proofs step by step.
Deduce also means to understand something by looking at signs or hints that are not clear. It is a careful guess based on evidence.
From her smile, I deduce she is happy.
You can deduce the truth from his eyes.
