Column Multiplication formula

[HLennen]

Hello everyone,

Very new to Excel here and I was wondering if there was a formula that would give me the sum of two columns without having to manually input the individual cell every time. For example Column A is a Qty of 2 and Column B is a unit price of $10.00. I know I can use =A1*B1 in order to get a total in Column C but I was wondering if there was a way for the Row number to autopopulate as well?

[#2]

@HLennen 

In C1 enter =A1*B1, select entire range (e.g. C1:C1000) and Ctrl+D

Or double click on the dot in right bottom when you stay on C1