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99 in words

99

ninety-nine

99 is written ninety-nine.

Ways to write it

As an ordinal: ninety-ninth
Roman numeral: XCIX
Expanded form: 90 + 9

Place value

Place	Digit	Value
tens	9	90
ones	9	9

Number facts

Even or odd: Odd
Prime or composite: Composite
Factors: 1, 3, 9, 11, 33 and 99 (6 factors)
First 10 multiples: 99, 198, 297, 396, 495, 594, 693, 792, 891, 990
Square: 99 × 99 = 9,801
Square root: ≈ 9.95
Sum of the digits: 9 + 9 = 18
Rounded to the nearest 10: 100
Number before: 98
Number after: 100
In binary: 1100011

Quick check

What number comes just after 99?
Show the answer
100
Is 99 even or odd?
Show the answer
Odd
What is 99 + 10?
Show the answer
109

Practice with a game

Count with Me

Count pictures up to 5, 10 or 20 and compare groups.

Place Value Quest

Ones, tens, hundreds and thousands.

Times Tables Challenge

Practice any times table from 2× to 12×.

Frequently asked questions

How do you write 99 in words?

99 is written "ninety-nine".

Is 99 a prime number?

No. 99 is a composite number, because it has more than two factors.

What are the factors of 99?

The factors of 99 are 1, 3, 9, 11, 33 and 99.

How do you write 99 in Roman numerals?

99 in Roman numerals is XCIX.