In the number 2345, the 2 is worth 2000 because it is in the thousands column. The 3 is worth 300 because it is in the hundreds column. The 4 is worth forty since it is in the tens column. The 5 is worth 5 since it is in the ones column.
See if you can figure out the answer to each of these:
What is the value of the digit in red? 2432 --> (30) 2812 --> (800) 3147 --> (7) 1462 --> (60) 7623 --> (7000)