Question Analysis:
We are given a number 427398 and we need to find the least number that must be subtracted from it so that the remaining number is divisible by 15.

Solution:
To find the least number that must be subtracted from 427398, we need to find the remainder when 427398 is divided by 15.

Step 1: Find the remainder when 427398 is divided by 15.
We can use the modulo operator to find the remainder. By performing the division, we get:
427398 ÷ 15 = 28493 remainder 3

Therefore, the remainder when 427398 is divided by 15 is 3.

Step 2: Find the least number that must be subtracted from 427398 so that the remaining number is divisible by 15.
To make the remaining number divisible by 15, we need to subtract the remainder (3) from 427398.

427398 - 3 = 427395

Now, let's check if 427395 is divisible by 15.

Step 3: Check if the remaining number (427395) is divisible by 15.
To check if a number is divisible by 15, we need to see if it is divisible by both 3 and 5, as 15 is a multiple of both 3 and 5.

To check if a number is divisible by 3, we can add up its digits and see if the sum is divisible by 3. In this case, the sum of the digits is:
4 + 2 + 7 + 3 + 9 + 5 = 30

Since 30 is divisible by 3, we can conclude that 427395 is divisible by 3.

To check if a number is divisible by 5, we need to see if its last digit is either 0 or 5. In this case, the last digit of 427395 is 5, so it is divisible by 5.

Since 427395 is divisible by both 3 and 5, we can conclude that it is divisible by 15.

Therefore, the least number that must be subtracted from 427398 so that the remaining number is divisible by 15 is 3.