Summary
The “tens fact” method is a way to solve subtraction problems by using known addition facts to 10. You show the tens fact you used, write the difference, and explain the thinking. For example, to solve 14 – 6, use the tens fact 10 – 6 = 4. Then add the extra 4 (from 14) to get 8. This method is common in Grade 1 and Grade 2 math and helps students build strong number sense.
5 Key Takeaways
- A tens fact is a math fact that adds up to 10 (like 6 + 4 = 10).
- The “show the tens fact you used” method uses tens facts to solve subtraction.
- It builds strong number sense in young learners.
- The steps are: identify the tens fact, use it, write the difference, explain.
- Common in Grade 1-2 math (Common Core and similar programs).
Introduction
Elementary math sometimes asks students to “show the tens fact you used” and then “write the difference.” Parents often see this on homework and wonder what it means. This post explains the method, gives clear examples, and shows how to teach it at home.
What Is a Tens Fact?
A tens fact is any pair of numbers that adds up to 10. Common examples:
- 1 + 9 = 10
- 2 + 8 = 10
- 3 + 7 = 10
- 4 + 6 = 10
- 5 + 5 = 10
Kids memorize these tens facts because they make bigger math easier.
What the Instruction Means
“Show the tens fact you used” asks a student to name the tens fact they picked to solve the problem.
“Write the difference” means write the answer to the subtraction.
Together, the student shows their thinking and the final answer.
Simple Example
Problem: 12 – 5 = ?
- Break 12 into 10 + 2.
- Use the tens fact 10 – 5 = 5.
- Add the 2 back: 5 + 2 = 7.
- Write: Tens fact used: 10 – 5 = 5. Difference: 7.
Quick Reference: Common Tens Facts and Uses
| Problem | Tens Fact Used | Difference |
|---|---|---|
| 13 – 5 | 10 – 5 = 5 | 8 |
| 14 – 7 | 10 – 7 = 3 | 7 |
| 15 – 8 | 10 – 8 = 2 | 7 |
| 16 – 9 | 10 – 9 = 1 | 7 |
| 17 – 8 | 10 – 8 = 2 | 9 |
Why Kids Learn This
Tens fact subtraction helps kids:
- Build strong mental math
- Skip finger counting
- Understand place value
- Prepare for two-digit subtraction
- Feel confident with numbers
It also teaches thinking — not just memorization.
The Steps a Student Follows
- Look at the subtraction problem.
- Break the top number into 10 + the rest.
- Use the tens fact (10 minus the bottom number).
- Add the “rest” back to that answer.
- Write the difference.
This becomes fast with practice.
Another Example: 15 – 9
- 15 = 10 + 5.
- Tens fact: 10 – 9 = 1.
- Add the 5 back: 1 + 5 = 6.
- Answer: 15 – 9 = 6.
- Written form: Tens fact: 10 – 9 = 1. Difference: 6.
Common Mistakes Students Make
- Forgetting to add the extra ones back
- Subtracting the wrong number
- Writing the tens fact wrong
- Skipping the “show your work” step
- Guessing without explaining
Show your child how to check by doing the math a second way.
How to Help at Home
Use Objects
Coins, blocks, or beans work. Group 10 items in one pile and the rest in another. Take away the number being subtracted.
Play Ten Frames
Ten frames are grids of 10 boxes. Fill part of the grid with dots. Take some away. Count what is left.
Say It Out Loud
Have your child say the steps: “10 minus 6 is 4. Plus 3 more is 7.”
Show, Then Do
Model one problem. Then let your child do the next.
How Teachers Score This
Most teachers look for two things:
- The tens fact is correct
- The difference (final answer) is correct
Showing the work matters as much as the answer. Points are given for both.
Sample Homework Question
Question: Solve 13 – 8. Show the tens fact you used. Write the difference.
Answer:
- Tens fact: 10 – 8 = 2
- Add the 3 (from 13) back: 2 + 3 = 5
- Difference: 5
Why the Method Is Better Than Counting
Counting on fingers is slow. Tens facts are fast. Once memorized, they help with:
- Bigger subtraction problems
- Multi-digit math
- Mental math in daily life
- Math tests where speed matters
- Feeling confident with numbers
Related Math Skills
- Doubles facts (5 + 5, 6 + 6)
- Making 10 to add (7 + 6 = 7 + 3 + 3)
- Place value (tens and ones)
- Fact families (7 + 3 = 10, 10 – 3 = 7)
Each one supports strong number sense.
Common Questions
What does “show the tens fact you used” mean?
It means write the tens fact that helped you solve the subtraction.
What is a “difference” in math?
The answer to a subtraction problem.
Is this Common Core math?
Yes. It shows up in Common Core Grade 1 and Grade 2 standards.
Why not just teach memorization?
Memorization plus understanding works better long-term.
How do I help my child if I do not know it?
Learn together with a short YouTube video. Break the problem into pieces.
Is there a shortcut?
Practice tens facts until they are automatic. That is the shortcut.
What ages use this?
Most kids learn it in first and second grade.
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Practical Tips for Parents
- Practice tens facts 5 minutes a day
- Use coins or blocks to make it visual
- Ask your child to explain their steps out loud
- Celebrate progress, not just correct answers
- Reach out to the teacher if something is confusing
- Try free math game websites for extra practice
Conclusion
“Show the tens fact you used, write the difference” is a common elementary math instruction. It asks students to name the tens fact they used to solve a subtraction problem and then write the final answer. The method builds strong number sense and prepares kids for bigger math.
Practice with objects, ten frames, and short daily sessions. Once your child masters tens facts, subtraction becomes fast and confident — and math homework stops being a struggle.
