Chapter 1 - Whole Numbers - 1.2 Adding Whole Numbers - 1.2 Exercises - Page 18: 4

$83+15=98$

First, add the digits in the ones column (each number's ones place) to determine the digit in the ones place of the sum: $3+5=8$ Next, add the digits in the tens column (each number's tens place) to determine the digit in the tens place of the sum: $8+1=9$ If the sum has $9$ in the tens place and $8$ in the ones place, it must be $98$.