Do you ever stare at a simple subtraction and wonder if you can turn it into a neat ten?
It’s the kind of brain‑teaser that shows up in school quizzes, on puzzle blogs, or in those “mind‑bending” TikToks that keep you scrolling. The trick isn’t just math; it’s a little bit of lateral thinking, a dash of creativity, and a lot of practice.
What Is “Make a Ten to Solve 13 7”
When people say “make a ten to solve 13 7” they’re usually talking about a classic arithmetic puzzle: you’re given the numbers 13 and 7, and you’re asked to use them (and sometimes the digits that make them up) to arrive at the number 10. The goal is to find a clever way to transform the original expression so that the result is exactly ten Easy to understand, harder to ignore. Less friction, more output..
In practice, the puzzle is often phrased like this:
“Use the numbers 13 and 7 (and only those numbers) to make the number 10.”
You’re allowed to add, subtract, multiply, divide, and even rearrange the digits, but you can’t bring in any new numbers. It’s a great exercise for sharpening mental math and spotting patterns.
Why It Matters / Why People Care
You might ask, “Why bother with a puzzle that seems so trivial?” Here are a few reasons that make it worth your time:
- Brain health: Quick mental calculations keep the brain engaged and help ward off cognitive decline.
- Test prep: Many standardized tests include similar “number tricks” that reward creative thinking.
- Daily life: You’ll find yourself using this mindset when you’re budgeting, cooking, or even planning a trip.
- Fun factor: It’s a quick way to impress friends or break the ice at a party.
When you master this kind of puzzle, you’ll notice that you start seeing opportunities to simplify problems in real life. That’s the real payoff Not complicated — just consistent. Took long enough..
How It Works (or How to Do It)
Let’s walk through the puzzle step by step. Here's the thing — the core idea is to manipulate the given numbers so that the final expression equals ten. Below are the common strategies, broken down into bite‑size chunks Simple, but easy to overlook..
### 1. Break the Numbers into Digits
Instead of treating 13 and 7 as whole numbers, split them:
- 13 → 1 and 3
- 7 → 7
Now you have the digits 1, 3, and 7 to play with. This opens up more possibilities because you can combine them in different ways Easy to understand, harder to ignore..
### 2. Use Basic Operations
The most straightforward operations are addition, subtraction, multiplication, and division. Try each in turn to see if any combination lands you on ten.
Example:
- 13 – 7 = 6
- 13 + 7 = 20
Neither gives ten, but they’re the starting points.
### 3. Combine Operations
You can nest operations. Take this case: you might subtract 7 from 13, then add something else to reach ten Easy to understand, harder to ignore..
Example:
- 13 – 7 = 6
- 6 + 4 = 10
So you need to create the number 4 using the remaining digits (1, 3, 7). That’s where the next step comes in Worth keeping that in mind. Which is the point..
### 4. Build the Missing Number
Using the digits 1, 3, and 7, create the number 4. One clever trick:
- 7 – 3 = 4
Now plug that back into the earlier expression:
- (13 – 7) + (7 – 3) = 6 + 4 = 10
Voila! You’ve made a ten The details matter here..
### 5. Check for Other Solutions
Sometimes You've got multiple ways worth knowing here. It’s a good idea to verify that you didn’t miss a simpler or more elegant solution. Here’s an alternative:
- 13 – (7 – 3) = 13 – 4 = 9
- 9 + 1 = 10
Notice how we used the digit 1 at the end. Both solutions are valid; the puzzle often accepts any correct method Surprisingly effective..
Common Mistakes / What Most People Get Wrong
-
Forgetting to use all the digits
Many people think it’s okay to ignore a digit. The challenge usually requires you to use every given number or digit at least once Simple, but easy to overlook.. -
Assuming only whole‑number operations
Division that results in a fraction is often overlooked, but it can be part of a valid solution if you end up with a whole number Most people skip this — try not to.. -
Getting stuck on the first approach
If subtraction doesn’t work, try addition or multiplication first. The brain loves patterns, so a fresh angle can reveal a hidden path Not complicated — just consistent.. -
Misreading the puzzle
Some puzzles ask you to create the number ten from the digits in 13 and 7, not from the numbers themselves. That changes the strategy completely No workaround needed..
Practical Tips / What Actually Works
-
Write it down
Jotting the digits on paper can help you see combinations you might miss mentally. -
Play with parentheses
Grouping numbers changes the order of operations. Take this: (13 – 7) + (7 – 3) is different from 13 – (7 + 7 – 3). -
Use the “difference” trick
Subtracting one digit from another often yields a small number that can fill the gap to ten Easy to understand, harder to ignore.. -
Look for symmetry
If you can split the expression into two parts that mirror each other, you’re often on the right track. -
Practice variations
Try the same puzzle with different numbers (e.g., 12 and 8, 15 and 5). The more you practice, the faster you’ll spot the pattern Not complicated — just consistent..
FAQ
Q1: Can I use multiplication or division?
Yes, as long as the final expression equals ten and you only use the given numbers/digits Worth knowing..
Q2: Do I have to use every digit once?
Most puzzles require it, but check the specific rules. If not, you can still make a ten, but the challenge loses some of its charm Worth knowing..
Q3: What if I can’t find a solution?
Double‑check the rules. Sometimes the puzzle has a trick, like using a decimal or a factorial. If it’s still impossible, the puzzle might be flawed Worth knowing..
Q4: Is there a software that can solve this automatically?
Sure, but the fun is in the mental exercise. Use a calculator only if you’re stuck after a few minutes.
Q5: How can I teach this to kids?
Start with simple numbers (e.g., 5 and 3) and let them experiment. Celebrate every correct attempt, even if it’s not the most efficient route Small thing, real impact..
Closing
Puzzles like “make a ten to solve 13 7” are more than brain teasers; they’re practical exercises in flexible thinking. On top of that, by breaking the problem into smaller pieces, trying different operations, and keeping an eye out for common pitfalls, you’ll find yourself solving them faster and more elegantly. So next time you see a pair of numbers staring at you, remember: with a little creativity, you can turn any pair into a perfect ten Took long enough..
