Math Help: Long Multiplication Problems

How to Help Your Child with Long Multiplication

Typically, children learn basic multiplication in third grade and start working with long multiplication later in elementary school. If your child is struggling with long multiplication, you may want to make sure he or she is comfortable with basic multiplication facts, which you can do by giving him or her timed quizzes or reviewing using flashcards.

Once your child has mastered the basics, help him or her with long multiplication by providing extra practice at home and walking through the steps together. For example, consider the problem 180 x 30. First, show your child how to multiply every number in the second factor (30) by every number in the multiplier (180). Then, add the products together to find the final answer, which is 5,400.

If your child continues to struggle, you might write out a sample problem that he or she can use as a model while completing homework. And remember, the more practice your child gets with the long multiplication process, the more he or she will come to understand it.

Long Multiplication Problems

1. 256 x 41

Your child should begin by multiplying the 1 in 41 by all the numbers in the multiplier, like this: (1 x 6), (1 x 5) and (1 x 2). The product is 256. Then, he or she should write a zero in the ones column and multiply the 4 in 41 by all the numbers in the multiplier, like this: (4 x 6), (4 x 5) and (4 x 2). The product is 10,240. Finally, your child should add the two products together so that the final answer is 10,496.

2. 641 x 5,199

Remind your child that solving these problems using a calculator defeats the purpose and that, no matter how large the numbers involved, the steps in long multiplication remain the same. This can help build his or her confidence. The answer to this problem is 3,332,559.

3. 862 x 19

The product is 16,378. Sometimes, students forget to add the zero in the ones column before multiplying the second number in the factor (the 1 in 19). If your child's answer isn't correct, look for that mistake first.

4. 1.10 x 5

For a challenge, you can throw in a problem using decimals. There should be two places after the decimal point in the answer because it should match the numbers in the question. The answer is 5.50.