Multiplying big numbers, like 213 × 32
In 5th grade, children learn to multiply larger whole numbers, like 213 × 32, using the standard written method.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
Try these with your child
These are real questions from our 5th grade practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
Each apple tree in an orchard grows 30 apples. The orchard has 120 trees. How many apples do the trees grow?
- 36,000
- 3,600
- 150
Why this matters
Confidence with big multiplication frees your child to focus on the harder thinking ahead. Dividing by two-digit numbers, multiplying decimals, and finding volume all lean on it this year, and in middle school it sits underneath ratios, percentages, and area problems. A child who still has to fight through 24 × 36 often loses the thread of the bigger problem it was part of.
Where kids can get stuck
- Forgetting the placeholder zero, so 213 × 32 becomes 426 + 639 = 1,065 instead of 6,816.
- Mixing up the small carried digits, adding one from multiplying by 2 into the row for multiplying by 30.
- Misaligning the columns of partial products, so tens sit under hundreds and the total is far off.
How you can help
- Estimate before multiplying: for 213 × 32, ask your child to round to 200 × 30 = 6,000. Then compare that estimate with their exact answer to see whether it is reasonable.
- Use a real situation at home, like how many minutes are in 14 days of 45-minute practice sessions, 14 × 45, and let your child work it out on paper, then check it together.
- Ask your child to teach you their method with a two-digit by two-digit problem from the grocery store, such as 12 cans at 89 cents each. Listen for why the second row starts with a zero.
Want a little more? Try Bobby's Math Club for free practice that adapts to your child.
Questions parents ask
Why is my child learning the standard algorithm only now, in 5th grade?
Earlier grades used area models and partial products so your child would understand what multiplication by tens and ones actually does. The standard algorithm is a compact version of those same steps. Learning the meaning first makes the shortcut less mysterious and makes mistakes like dropping the placeholder zero easier to catch. Fifth grade is when fluency with the written method is expected.
My child still uses the box method. Is that a problem?
The box or area method is a sound strategy and shows real understanding of place value. By the end of 5th grade, children are expected to use the standard algorithm fluently, so it helps to connect the two. Ask your child to do a problem both ways and point out where each partial product in the box appears in the stacked method.
What if my child's multiplication facts are not automatic yet?
Multi-digit multiplication depends on single-digit facts, so slow facts can make every problem feel long and lead to small errors. Your child can still learn the method while facts improve. Short, regular fact practice in daily moments, such as quick questions in the car, often helps more than long sessions. Using an estimate to check answers also catches many fact slips.
Make learning math fun
Bobby's Math Club turns 5th grade math practice into something fun to do together.
- Free, unlimited practice for every child in your family
- Practice that starts where your child is and grows with them
- Level-ups, badges, and a cheer for every win
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
Ready to watch your child’s confidence grow?
Your 5th grade child can start today with free, unlimited practice that grows with them.
Join the clubNote for teachers: This skill is covered by Common Core math standard 5.NBT.B.5: “Fluently multiply multi-digit whole numbers using the standard algorithm.” Learn how Bobby's Math Club can help your students grow. (Common Core 5.NBT.5)