How to Teach a Child to Carry Numbers

Children are often confused and mystified by the need to carry numbers in addition and multiplication. It's up to you to unveil the secrets and make it simple. Hope you're ready to unleash your inner math teacher!

Method 1

Method 1 of 2:

Addition

Have the child learn (and memorize) the basic addition facts.
Draw a line between the "units" and the "tens" column to help align and use "place values" in columns. It is not important for your child to already know how to do two column addition.
Do not have them put a "1" over the numbers, yet.
Make certain the child places the digit(s) in the correct position (no digit should be in the units column.) If they are confused, cover up the units column. Have the child write the number(s) underneath the number already written in the "tens" column from the "units" column addition.
5
Tell the child that the problem is not finished. Review what you have completed so far.
- If you were using the example above, you might say, "We're almost done. You did seven plus five equals twelve. Good. Four plus three equals seven. Correct. Notice that the four and the three are in the tens position, so you are really adding forty and thirty."
Have the child bring the amount in the units column down to the bottom. Point to the numbers in the "tens" column and ask the child to add them up.
By now, the child should already be familiar with the commutative law of addition or (at least) know that the order of addition is unimportant.
Tell the child that this is a shortcut we call "carrying", and more commonly called "regrouping" in classrooms today.
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Method 2

Method 2 of 2:

Multiplication

This is a more complicated version of the method used in addition. A fringe benefit of this method is that it reveals why estimation works. Before you begin,

2
Teach the child how to handle multiples of ten; we see this as zeros on the end of a number.
- Simply put: Anytime you multiply by a number with zeros on the end (like 120 x 160), you add the number of zeros to the end of the product.
  120 x 160 becomes:
  12 * 16 = 192
  Place the two zeros on the end (One from 120 and another from 160)
  = 19,200
  Start with a one digit times two digit multiplication problem
5
Before multiplying the Units column by the Tens column, discuss the implications.
- Remind the child that the units column has already been multiplied. Tell the child that when you multiply the units column by the tens column it's like multiplying something with a zero on the end.
Multiply the Units column by the tens column and place the answer to the left side of the zero (it will be underneath the first answer).
8
Have the child add the numbers together.
- Do not continue until the child can manage any problem of this type (1 x 2)! Continue with a two digit times two digit (2 by 2) multiplication problem. Most children have no idea why their teacher skips a space on the second line of "conventional" long multiplication.
Mark the two multiplications (which will look like a big X).
Again, have the child place a zero(0) in the right hand column and answer the units x tens multiplication to the left of the zero.
Show the child that this is like multiplying by 100. Have the child place zeros in the two right columns and place the product to the left.
Put it together with unit times two digit (1 by 2) multiplication
15
This time, instead of writing the tens digit (from the unit x unit product) under the line, write it ABOVE the tens digit column.
- Have the child compare this to carrying in addition.
16
Have the child do the units times tens multiplication; have the child add the carried number to the product and write the number to the left of the units digit already present.
- The child should become proficient at this before proceeding.
  Complete the process of (2 by 2) multiplication.
18
Have the child treat the tens digit like the other one times two digit work. Remind the child of the zero in the right column.
- This would be a good time to tell the child that the zero in the right hand column is not necessary, but it won't hurt if they leave it.
EXPERT TIP
Joseph Meyer
Math Teacher
Joseph Meyer is a High School Math Teacher based in Pittsburgh, Pennsylvania. He is an educator at City Charter High School, where he has been teaching for over 7 years. Joseph is also the founder of Sandbox Math, an online learning community dedicated to helping students succeed in Algebra. His site is set apart by its focus on fostering genuine comprehension through step-by-step understanding (instead of just getting the correct final answer), enabling learners to identify and overcome misunderstandings and confidently take on any test they face. He received his MA in Physics from Case Western Reserve University and his BA in Physics from Baldwin Wallace University.
Joseph Meyer
Math Teacher
Explore multiplication learning tool options. Multiplication grids, pegboards, electronic boards, and tiles offer a hands-on, engaging way to practice multiplication. Unlike flashcards that show a single problem, these tools can display multiple problems at once, helping you identify patterns and fast-track memorization.
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Question
What are some multiplying tricks that I can teach my child?
David Jia
Math Tutor
David Jia is an Academic Tutor and the Founder of LA Math Tutoring, a private tutoring company based in Los Angeles, California. With over 10 years of teaching experience, David works with students of all ages and grades in various subjects, as well as college admissions counseling and test preparation for the SAT, ACT, ISEE, and more. After attaining a perfect 800 math score and a 690 English score on the SAT, David was awarded the Dickinson Scholarship from the University of Miami, where he graduated with a Bachelor’s degree in Business Administration. Additionally, David has worked as an instructor for online videos for textbook companies such as Larson Texts, Big Ideas Learning, and Big Ideas Math.
David Jia
Math Tutor
Expert Answer
Here's a trick for children when multiplying by nines: If you're multiplying a single digit by nine, use your fingers. For example, if it's three times nine, hold down your third finger. The number of fingers to the left of the held-down finger represents the first digit of your answer. This visual method helps children quickly and intuitively find the result when multiplying by nines.
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What is the answer of doubling 41?
Akitagem
Community Answer
To double 41, you should think of 41+41. Your final answer would be 82.
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How do I develop the concept of subtraction in teaching elementary students?
Donagan
Top Answerer
Use a set of physical objects such as blocks. For example, start with five blocks. Take away two blocks. You're left with three blocks.
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