Long Multiplication: 90 × 9

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

What is 90 × 9?

Answer

90 × 9 =
810

90 × 9 and 9 × 90 are the same product — the order of the factors never changes the answer, only the working. Below, 90 is multiplied by 9 in a column, digit by digit.

90 × 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.

  90
×  9
 810
90 × 9 = 810

Step-by-Step Solution

Step 1: Multiply the multiplicand by the last digit of the multiplier, 9: 90 × 9 = 810.

  • 0 × 9 = 0. Write 0.
  • 9 × 9 = 81. Write 1 and carry 8.
  • No digits are left, so the carried 8 is written in front: the partial product is 810.

90 × 9

=

810

Check It, and What It Is Not

Check by dividing back. Multiplication and division undo each other, so 810 ÷ 9 = 90 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.

90 × 9 is a number, not an area. If those are the sides of a room in feet, the answer is 810 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 90 × 9? (The answer is: 810). Enter the multiplicand (e.g. '90') and the multiplier (e.g. '9') and hit the button. The order of the two numbers does not matter — 90 × 9 and 9 × 90 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 90

MultiplicationProduct
80 × 9720
81 × 9729
82 × 9738
83 × 9747
84 × 9756
85 × 9765
86 × 9774
87 × 9783
88 × 9792
89 × 9801
90 × 9810
91 × 9819
92 × 9828
93 × 9837
94 × 9846
95 × 9855
96 × 9864
97 × 9873
98 × 9882
99 × 9891

FAQ

What is 90 × 9?

90 × 9 = 810

Is 90 × 9 the same as 9 × 90?

Yes. Multiplication is commutative, so both come to 810. Only the working differs: this page multiplies by 9, which gives a single partial product.

How do you check that 90 × 9 = 810?

Divide the product back by one of the factors: 810 ÷ 9 = 90 exactly, with no remainder. Multiplication and division undo each other, which is what makes this check work.

What are the partial products of 90 × 9?

There is only one: the multiplier 9 has a single digit, so 90 × 9 = 810 is written straight under the line, with no addition step.

See Also