## How many two digit numbers are there with two digits different?

Answer: The total number of two digit numbers is 90. From 1 to 99 there are 99 numbers, out of which there are 9 one-digit numbers, i.e., 1, 2, 3, 4, 5, 6, 7, 8 and 9. If one digit numbers are subtracted from 99 we get 90 two-digit numbers.

**How many 2 digits are there?**

90

Therefore, the total number of 2-digit numbers which can be obtained are 90.

**How many 2-digit numbers are there from 100?**

The number name of 75 is seventy-five. Example 3: Write the first four ‘2-digit numbers’ and the last four ‘2-digit numbers’. Solution: The first four two-digit numbers are: 10, 11, 12, 13. The last four two-digit numbers are: 96, 97, 98, 99.

### How many 2-digit numbers are there in 5*9?

(a) If repetition is allowed, we have 5 choices for the units digit (any of the 5 even digits); then we have 9 choices for the tens digit (any digit except 0). That makes 5*9 = 45 2-digit numbers. (b) If repetition is not allowed, then there are two cases to consider.

**How many 2-digit numbers can be formed from 4 choices?**

It depends on whether repetition is allowed or not: (1) Repetition allowed : There are 4 choices for both positions, so [math]4 \imes 4 = 16[/math] 2-digit numbers can be formed. (2) Repetition not allowed : There are 4 options for tens position, and three options for ones position.

**What is the total number of possible 2-digit even numbers?**

Of the 10 digits, 5 are even. So in both cases there are 5 choices for the units digit of the 2-digit number. (a) If repetition is allowed, then there are 10-1 = 9 choices for the tens digit. (9 because you can not use zero as the “tens” digit). The total number of possible 2-digit even numbers is 9*5 = 45, if repetition is allowed .

## How many two-digit numbers are there in base 4?

What this really amounts to is base 4. We know that the total of one and two digit numbers in base 4 is 4 squared or 16. And we know the total number of single digit to be 4. Thus the total number of 2 digit numbers would be: The answer is 12 two digit numbers.