Category Multi-digit Addition

Carrying to the right--when the sum of each digit exceeds 10, the value of the resulting tens digit or hundreds digit is not properly combined with the tens digit or hundreds digit.

Making up extra digit- when the sum of two single digits exceeds 10, the value of the resulting ten's digit is improperly combined with the sum of the tens digits.

Ignoring place value-when multi-digit numbers are added, each digit is added without its corresponding place value.