Long Multiplication: 420 × 9

Long Multiplication Calculator
Multiplicand (number to be multiplied)
Multiplier (number to multiply by)

What is 420 × 9?

Answer

420 × 9 =
3,780

420 × 9 and 9 × 420 are the same product — the order of the factors never changes the answer, only the working. Below, 420 is multiplied by 9 in a column, digit by digit.

420 × 9 in a Column

The multiplicand goes on top, the multiplier underneath, both aligned on the right. The multiplier has a single digit, so there is one partial product and the answer goes straight under the line.

  420
×   9
 3780
420 × 9 = 3,780

Step-by-Step Solution

Step 1: Multiply the multiplicand by the last digit of the multiplier, 9: 420 × 9 = 3,780.

  • 0 × 9 = 0. Write 0.
  • 2 × 9 = 18. Write 8 and carry 1.
  • 4 × 9 = 36, plus the carried 1 makes 37. Write 7 and carry 3.
  • No digits are left, so the carried 3 is written in front: the partial product is 3,780.

420 × 9

=

3,780

Check It, and What It Is Not

Check by dividing back. Multiplication and division undo each other, so 3,780 ÷ 9 = 420 must come out exactly, with no remainder.

Fractions are a different calculation. Both factors here are whole numbers; for 2/3 or 2 3/4 use the fraction multiplication calculator, which multiplies numerators and denominators separately.

420 × 9 is a number, not an area. If those are the sides of a room in feet, the answer is 3,780 square feet — the same arithmetic, a different question, and it is answered by the square footage calculator.

Related Calculations

See Also

Long Multiplication Calculator

This calculator multiplies two whole numbers the way it is done on paper: digit by digit, carrying where the column overflows, then adding the partial products together. For example, it can help you find out what is 420 × 9? (The answer is: 3,780). Enter the multiplicand (e.g. '420') and the multiplier (e.g. '9') and hit the button. The order of the two numbers does not matter — 420 × 9 and 9 × 420 are the same product — so either number can go on top. Fractions and mixed numbers belong to the fraction multiplication calculator, and the reverse operation is long division.
Recalculate with different values ↑

Products of 420

MultiplicationProduct
320 × 92,880
330 × 92,970
340 × 93,060
350 × 93,150
360 × 93,240
370 × 93,330
380 × 93,420
390 × 93,510
400 × 93,600
410 × 93,690
420 × 93,780
430 × 93,870
440 × 93,960
450 × 94,050
460 × 94,140
470 × 94,230
480 × 94,320
490 × 94,410
500 × 94,500
510 × 94,590

FAQ

What is 420 × 9?

420 × 9 = 3,780

Is 420 × 9 the same as 9 × 420?

Yes. Multiplication is commutative, so both come to 3,780. Only the working differs: this page multiplies by 9, which gives a single partial product.

How do you check that 420 × 9 = 3,780?

Divide the product back by one of the factors: 3,780 ÷ 9 = 420 exactly, with no remainder. Multiplication and division undo each other, which is what makes this check work.

What are the partial products of 420 × 9?

There is only one: the multiplier 9 has a single digit, so 420 × 9 = 3,780 is written straight under the line, with no addition step.

See Also