Mental Math Tricks for Kids

Magic looks impressive—but understanding lasts

A child watches an adult multiply 9 × 7 instantly and hears, “It’s just a trick—put down your seventh finger and read the answer.” The digits appear like magic: 63. Impressive? Yes. Durable? Often no—because the trick hides the reasoning. Contrast that with another child who says, “Nine sevens is ten sevens minus one seven: 70 − 7 = 63.” Same answer, different foundation. One performer memorized steps; the other owns a strategy.

This article is about the second kind: mental math moves that teach something transferable. A good “trick” is really a shortcut with an explanation attached. If your child cannot say why it works, treat it as entertainment until the why arrives. For the broader philosophy, start with what mental math is.

How to judge whether a trick is worth teaching

Run each shortcut through three questions before adopting it:

• Can my child explain it in one sentence? “I took one from seven and gave it to nine to make ten” passes. “I do the finger thing” does not.
• Does it work beyond one example? A rule that only handles 9 × 7 but fails for 9 × 4 is a party stunt, not a tool.
• Does it connect to something they already know? The best tricks are compressed versions of make-ten, compensation, or the distributive property—not unrelated hacks.

When a shortcut passes all three, name the strategy behind it. “This is make-ten wearing a costume.” That framing prevents tricks from competing with real mathematics.

Addition tricks that actually teach

Addition shortcuts succeed when they respect place value rather than treating digits as isolated symbols. Before introducing any trick, ask your child to estimate: “Will the answer be closer to forty or sixty?” Estimation anchors tricks in sense-making and catches wild errors early.

Make-ten for 7 + 8: Seven needs three to reach ten; take three from eight, leaving five. Ten plus five equals fifteen. The move works because addition allows rearrangement without changing the total. Practise the pattern in Stage 2: Making Tens.

Doubles-plus-one nearby: Seven plus eight is one more than seven plus seven. Because 7 + 7 = 14, add one to get 15. This “near double” trick connects to Stage 7: Doubling and Halving and gives children who know doubles a fast path to odd pairs like 6 + 7 or 8 + 9.

Near-ten bump for 46 + 9: Forty-six is four away from fifty. Take four from the nine, leaving five. Fifty plus five equals fifty-five. Alternatively, treat nine as ten minus one: 46 + 10 = 56, minus 1 = 55. Compare both routes; children often prefer one. Near-ten work continues in Stage 4: Adding Near Tens.

Left-to-right tens first: For two-digit sums, add tens before ones to keep the largest parts visible. It feels like a trick to children trained on columns, but it is standard mental practice—see Stage 3: Left-to-Right Addition.

Bridge through a landmark: When an addend sits just below a round number, push it to the landmark first. Fifty-eight plus seven becomes sixty plus five. Bridging is covered in Stage 8: Bridging Through Tens.

Subtraction tricks with honesty about borrowing

Count up instead of subtract down for 73 − 28: Start at 28. Jump to 30 (+2), to 70 (+40), to 73 (+3). Total jump: 2 + 40 + 3 = 45. Counting up treats subtraction as finding the distance between numbers—a often clearer mental model than regrouping columns.

Round the subtrahend, then adjust: Treat 28 as 30. Seventy-three minus thirty is forty-three—but you subtracted two too many, so add two back: 45. This compensation mirror addition tricks children may already trust.

Split by place value: Subtract tens, then ones: 73 − 20 = 53, then 53 − 8 = 45. If ones go negative, bridge: 53 − 8 = 53 − 3 − 5 = 45. Each step stays small enough to hold in memory.

Avoid presenting subtraction tricks as “always faster.” For some numbers, written work is clearer. Mental tools win when they reduce steps, not when they impress adults.

Multiplication tricks grounded in groups

Distributive split for 6 × 8: Six eights is five eights plus one eight: 40 + 8 = 48. Or six fives plus six threes: 30 + 18 = 48. Splitting is the most reliable “trick” because it always works. Deepen it in Stage 14: The Distributive Property.

Nine as ten minus one for 9 × 7: Ten sevens are 70; subtract one seven to get 63. The finger trick for nines can reinforce this if you connect each finger to “one less group of ten.” Dedicated nine-and-eleven work lives in Stage 15: Multiplying by 9 and 11.

Double a known half for 6 × 8: If 3 × 8 = 24 is solid, double to 48. Doubling chains appear in Stage 7: Doubling and Halving.

Skip-count rhythm: Whisper “8, 16, 24, 32, 40, 48” for six steps. Skip counting is a legitimate bridge in Stage 11: Skip Counting until direct recall arrives.

Connect every multiplication trick to equal groups in Stage 12: Multiplication as Groups so symbols never float free of meaning.

When not to use a trick

Skip the shortcut when:

• Your child cannot explain why it works after two demonstrations.
• The trick only handles a narrow case (e.g., multiplying by 9 when both digits are single, but failing for 9 × 12).
• Anxiety rises—performance tricks under time pressure can feel like judgment, not play.
• The problem is already easy with a simpler strategy. Do not deploy the distributive property for 2 × 5 when “two fives” suffices.
• Accuracy drops. A fast wrong answer is worse than a slow correct one with explanation.

Tricks are seasoning, not the meal. Core strategies—make-ten, compensation, left-to-right addition, distributive splitting—should carry most of the weight.

A parent script: “How did you know?”

The question “How did you know?” turns a finished answer into a teachable moment. Use it consistently but warmly—not as an interrogation after every correct response.

After 46 + 9: “How did you know?” → “I went to fifty first.” → “Show me that on your fingers or a sketch.”

After 73 − 28: “How did you know?” → “I counted up from twenty-eight.” → “Where did you land first?” → “Thirty, then seventy, then seventy-three.”

After 6 × 8: “How did you know?” → “Five eights plus one eight.” → “What is five eights?” → “Forty.”

If the answer is “I just knew,” ask a gentler follow-up: “Could you check it a different way?” If no alternative exists, the fact may be memorized without structure—offer one reconstruction path and revisit tomorrow.

Praise the explanation, not only the number. “I like how you made ten” builds strategy identity; “You’re so smart” builds pressure to guess next time.

Building a weekly rhythm without burnout

Tricks stick when they appear in small, predictable doses—not as a Saturday-morning cram session before a school test. A sustainable week might look like this: Monday, one addition trick at the dinner table; Wednesday, a subtraction count-up on the walk home; Friday, one multiplication split before a favorite game. Three touchpoints beat one long drill because sleep and spacing strengthen memory.

Keep a simple log on the fridge: date, problem, strategy named, second-check method. After two weeks, patterns emerge. Maybe make-ten dominates addition while compensation wins for near-tens subtraction. That insight helps you choose the next stage lesson deliberately instead of guessing.

When a trick fails in real homework—your child uses a finger nine method and gets 9 × 6 wrong—treat it as data, not disaster. Ask which step broke. Rebuild with groups or the distributive split. Failed tricks are opportunities to deepen understanding, provided the tone stays curious rather than blaming.

Where to practise tricks that stick

Rotate short sessions across levels rather than bingeing one game:

• Make Ten Challenge for addition bonds.
• Mental Math Speed Round for mixed facts once explanations are steady.
• Beat the Clock Multiplication for times-table fluency with personal-best timing.

Supplement games with stage lessons linked above. Games motivate; stages teach. For speed without sacrificing understanding, read how to improve mental math speed.

Tricks for kids FAQ

Are finger tricks for nine times tables harmful?

Not if they connect to “ten groups minus one group.” Harm comes when fingers replace reasoning entirely. Pair any finger method with a verbal explanation and a check using another strategy.

My child prefers one trick and refuses other methods. Is that okay?

Preference is fine; refusal to consider alternatives is limiting. Require one backup method for assessment—“Show me another way to be sure”—without forcing them to abandon their favorite route daily.

How is this different from the shortcuts on social media?

Viral clips optimize for surprise. These strategies optimize for reuse. If a clip cannot survive the “how did you know?” test, treat it as entertainment, not curriculum.

When should we stop calling them tricks?

When your child can name the underlying strategy—make-ten, compensation, distributive property—drop the word “trick.” Language shapes identity: they are becoming mathematicians, not magicians.