Mental Math · Multiplication · M1
The single most powerful multiplication move: split one number into its place-value parts, multiply each part separately, then add. This is the distributive law, and once you own it you can multiply almost anything.
Watch the method
7 × 14 is hard, but 7 × 10 and 7 × 4 are easy. Split 14 into 10 + 4, multiply each by 7, then add: 70 + 28 = 98.
Multiply by the tens part of 14.
Multiply by the ones part of 14.
Add the pieces together.
Your turn
Use the method, then check. Stuck? Reveal the steps.
A number times (10 + 4) is the same as that number times 10, plus that number times 4. Splitting turns one hard product into two easy ones you already know.
Why it works
7 rows of 14 chairs = 7 rows of 10, plus 7 rows of 4.
6 × 23
Tens
6 × 20 = 120.
Ones
6 × 3 = 18.
Add
120 + 18 = 138.
7 × 14
Tens
7 × 10 = 70.
Ones
7 × 4 = 28.
Add
70 + 28 = 98.
7 × 123
Hundreds
7 × 100 = 700.
Tens
7 × 20 = 140.
Ones
7 × 3 = 21.
Add
700 + 140 + 21 = 861.
Splitting one number but forgetting to multiply BOTH parts.
Every part must be multiplied. 7 × 14 needs both 7×10 AND 7×4 — don't drop the ones.
Adding the parts before multiplying.
Multiply each piece first (70 and 28), THEN add. Order matters.
12 problems across three tiers. Auto-graded on submit. Hints and a full walkthrough on every question. Your work is saved on this device — sign in to keep it across devices.
t₁ = 5, d = 3 and t1=5,d=3 both count. For a list of numbers, separate them with commas (e.g. 3, 10, 17).7 × 14 = ?
6 × 23 = ?
8 × 12 = ?
5 × 34 = ?
7 × 26 = ?
9 × 23 = ?
6 × 45 = ?
8 × 35 = ?
12 × 14 = ?
13 × 23 = ?
7 × 123 = ?
6 × 214 = ?