Idiot\'s Guides Basic Math and Pre-Algebra

26 Part 1: The World of Numbers

Next, because you know that our next multiplication is by 3 tens and will add a zero, you’ll put a

zero under the ones digits. Then you’ll multiply each digit of 594 by 3, carrying when you need

to, and placing those digits on the line with that zero. It looks like this:

You start the second line of multiplication with the 0 on the right end, then multiply 594 v 3 to

get 1782. Finally, you’ll add the two lines of results to get your final product.

When you’re all done, you know that 594 v 32 = 19,008.

Notice that you’ve multiplied 594 by 2 and 594 by 30, then added those two products together.

The idea of adding that zero because you’re multiplying by a digit in the tens place can be

extended to other places. If you’re going to multiply by a digit in the hundreds place, you’ll put

two zeros at the right end of that line. If the digit you’re multiplying by is in the thousands place,

you’ll start the line with three zeros.

Here’s a larger problem with very simple multiplication, so that you can see how the plan works.

You can see that the zeros shift each line of multiplication over one place, and that’s because each

new multiplication is by a digit that’s worth ten times as much. The hardest part is all the adding,

but when you’re done 11,111 v 345 = 3,833,295.

594

32

1188

17820

21



594

32

1188

17820

19008

21

11

3

11,111

345

55,555

444,440

3,333,300

3,833,295

11

1