This is a 5-digit number.

The ones digit is the same as the thousands digit.

There is one 4 in the number.

The ones digit is the same as the last digit of last year's calendar year.

The ten thousands digit is five less than the thousands digit.

The last two digits sum to 15.

The number is 38,478

Step-by-step explanation:

* Lets explain how to find the number

- The number is 5-digit

* Ones ⇒ the last digit

* Tens

* Hundreds

* Thousands

* Ten thousand

- The ones digit is the same as the last digit of last year's calendar year

∵ The last year is 2018

∴ The last digit is 8

∴ The ones digit is 8

- The ones digit is the same as the thousands digit

∵ The ones digit is 8

∴ The thousands digit is 8

- The ten thousands digit is five less than the thousands digit

∵ The thousands digit is 8

∴ The ten thousands digit is 5 less than 8

∵ 8 - 5 = 3

∴ The ten thousands digit is 3

- The last two digits sum to 15

∵ The last two digits are ones and tens digits

∵ The ones digit is 8

∵ 15 - 8 = 7

∴ The tens digit is 7

- There is one 4 in the number

∵ The hundreds digit is empty

∴ The hundreds digit is 4

* The number is 38,478