245 × 13
When numbers get bigger, we use a method called the standard algorithm. Let's multiply two-hundred forty-five by thirteen.
Stack the numbers, lining the digits up by place value, and draw a line.
Start with the ones. Three times five is fifteen — write the five, and carry the one.
Three times four is twelve, plus the one we carried is thirteen. Write three, carry one.
Three times two is six, plus the one we carried is seven. Write seven. Our first partial product is seven-hundred thirty-five.
Now we move to the tens digit. First, drop a zero in the ones place to hold its spot.
One times five is five.
One times four is four.
One times two is two. Our second partial product is two-thousand four-hundred fifty.
Now add the two partial products together.
Two-hundred forty-five times thirteen is three-thousand one-hundred eighty-five. Great work!