multiply
US /ˈmʌl.tə.plaɪ/
UK /ˈmʌl.tə.plaɪ/

1.
increase or cause to increase greatly in number or quantity
:
•
The bacteria will multiply rapidly in warm conditions.
•
His problems seemed to multiply with each passing day.
2.
perform the process of multiplication
:
•
Can you multiply 7 by 8?
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We need to multiply these figures to get the total.