Number Card Puzzles
Number card puzzles ask you to arrange four digits into two 2-digit numbers that make a target sum. The trick is to use place value: tens digits do most of the work, and units digits fine-tune the total.
The Rules Every Number Card Question Uses
Each digit card must be used exactly once. You are building two 2-digit numbers, so each card must become either a tens digit or a units digit.
🔢 Rule 1: Use all four cards once
No digit can be repeated or ignored. The final answer must use every card exactly one time.
Example: Cards 8, 4, 7, 5 can make 58 + 47.
🏗️ Rule 2: Tens digits set the rough size
The two tens digits decide the main size of the sum. Choose them so their tens total is close to the target.
Example: Tens digits 5 and 4 make about 90 before the units are added.
🎯 Rule 3: Units digits finish the target
After choosing tens digits, check whether the two remaining unit digits complete the exact total.
Example: 58 + 47 = 105 because 8 + 7 gives the needed units and carry.
🔁 Rule 4: Some puzzles have paired answers
Swapping the two unit digits often gives another valid solution with the same total.
Example: 58 + 47 = 105 and 57 + 48 = 105.
How to Solve Number Card Puzzles
Three useful moves: choose sensible tens digits, test the units, and remember that swapped units may also work.
1. Build the Target from Place Value
Question: Use cards 8, 4, 7, and 5 to make two 2-digit numbers with a sum of 105.
Worked Method
Step 1: Choose tens digits that get close to the target. 5 and 4 give 90.
Step 2: Use the remaining cards as units: 58 + 47.
Step 3: Check the sum: 58 + 47 = 105.
Tip: Start with the tens digits because they change the total by 10s, not 1s.
2. Use the Units Swap
Question: Cards 9, 4, 3, and 8 must make a sum of 87.
Worked Method
Step 1: Try tens digits 4 and 3. That gives 40 + 30 = 70.
Step 2: The remaining units 8 and 9 add 17, so the total becomes 87.
Step 3: Two answers work: 48 + 39 or 49 + 38.
Tip: If the tens digits are correct, swapping the unit digits often gives the alternate answer.
3. Do Not Choose Tens Digits That Are Too Large
Question: Cards 9, 2, 8, and 4 must make a sum of 77.
Worked Method
Step 1: Avoid using 9 and 8 as tens digits because 90 + 80 is already too large.
Step 2: Use 4 and 2 as the tens digits: 40 + 20 = 60.
Step 3: The remaining units are 8 and 9, which add 17. So 48 + 29 = 77.
The trap: The biggest cards do not always belong in the tens places.
Before You Buy
Want to check the level and layout first? Download the free 3-question sample. It uses the same question style, printable format, and answer-key approach as the full pack.
Download Free Sample PDFGet the Full Practice Pack
The full Number Cards pack contains 90 puzzles across 3 printable test sets. Students practise mental addition, place value, target sums, and flexible number reasoning.
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