Long Multiplication: 100 × 9

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

What is 100 × 9?

Answer

100 × 9 =
900

100 × 9 and 9 × 100 are the same product — the order of the factors never changes the answer, only the working. Below, 100 is multiplied by 9 in a column, digit by digit.

100 × 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.

 100
×  9
 900
100 × 9 = 900

Step-by-Step Solution

Step 1: Multiply the multiplicand by the last digit of the multiplier, 9: 100 × 9 = 900.

  • 0 × 9 = 0. Write 0.
  • 0 × 9 = 0. Write 0.
  • 1 × 9 = 9. Write 9.

100 × 9

=

900

Check It, and What It Is Not

Check by dividing back. Multiplication and division undo each other, so 900 ÷ 9 = 100 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.

100 × 9 is a number, not an area. If those are the sides of a room in feet, the answer is 900 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 100 × 9? (The answer is: 900). Enter the multiplicand (e.g. '100') and the multiplier (e.g. '9') and hit the button. The order of the two numbers does not matter — 100 × 9 and 9 × 100 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 100

MultiplicationProduct
90 × 9810
91 × 9819
92 × 9828
93 × 9837
94 × 9846
95 × 9855
96 × 9864
97 × 9873
98 × 9882
99 × 9891
100 × 9900
110 × 9990
120 × 91,080
130 × 91,170
140 × 91,260
150 × 91,350
160 × 91,440
170 × 91,530
180 × 91,620
190 × 91,710

FAQ

What is 100 × 9?

100 × 9 = 900

Is 100 × 9 the same as 9 × 100?

Yes. Multiplication is commutative, so both come to 900. Only the working differs: this page multiplies by 9, which gives a single partial product.

How do you check that 100 × 9 = 900?

Divide the product back by one of the factors: 900 ÷ 9 = 100 exactly, with no remainder. Multiplication and division undo each other, which is what makes this check work.

What are the partial products of 100 × 9?

There is only one: the multiplier 9 has a single digit, so 100 × 9 = 900 is written straight under the line, with no addition step.

See Also