Question

My house number is a three-digit number. The sum of this number and its three individual digits is
129. What is the product of the three digits which make up the house number?
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Answer 1

Place Value of 3-Digit Numbers

Adding two three digit numbers (for example 529 + 733) involves several steps.
Place one number above the other so that the hundreds, tens and ones places are lined up. ...
Add the ones place digits (9 + 3 = 12). ...
Add the tens place digits (1 + 2 + 3 = 6) and place the answer below the line and in the tens place column.