At first glance, this looks like a normal vertical addition problem:

  253
+ 1?9
-----
  442

The missing digit is in the tens place of the second number.

Let’s solve it step by step.

Step 1: Add the ones column

The rightmost digits are:

3 + 9 = 12

Write 2 in the answer and carry 1 to the tens column.

So the ones column is correct.

Step 2: Add the tens column

Now look at the middle digits:

• Top number: 5
• Missing digit: ?
• Carry: 1

The result in the tens column is 4.

So:

5 + ? + 1 = 14

Because the answer shows 4 in the tens place, meaning the total must end in 4 while carrying 1 into the hundreds column.

Now solve:

5 + ? + 1 = 14

? = 14 − 6 = 8

So the missing number is 8.

Step 3: Check the hundreds column

Now verify:

• 2 (from 253)
• 1 (from 189)
• Carry 1

2 + 1 + 1 = 4

This perfectly matches the hundreds digit of the answer.

Final Check

  253
+189
----
 442

• Ones: 3 + 9 = 12 → write 2, carry 1
• Tens: 5 + 8 + 1 = 14 → write 4, carry 1
• Hundreds: 2 + 1 + 1 = 4

Everything matches perfectly.

Final Answer

The missing digit is 8.