Find the number of all four-digit numbers with numerals less than 7 (0;1;2;3;4;5;6), each of which is in order (from left to right) in descending order.

Question

The answer is 35. I need a solution.

Answer 1

You are correct....

You can figure it out using a tree diagram if you want...

but here they are....

6543 5432

6542 5431

6541 5430

6540 5421

5420

5410

5321

6532 5320

6531 5310

6530

6521 5210

6520

6510 4321

4320

4310

6432

6431 4210

6430

6421 3210

6420

6410

6321

6320

6310

6210