math prob

Test Preparation SAT Preparation
1

<p>In the integer 3589 the digits are all different and increase from left to right. How many integers between 4000 and 5000 have digits that are all different and that increase from left to right?</p>

<p>Does anyone know how to do this without just listing all the numbers?</p>

2

<p>Its 5C3 but i don’t quite understand why.</p>

3

<p>Is the answer 10?</p>

4

<p>The answer is 10</p>

5

<p>4567
4568
4569
4578
4579
4589</p>

<p>4678
4679
4689</p>

<p>4789</p>