Final answer:
When adding a whole number to a number with two digits after the decimal point, the sum should have 1 digit after the decimal point.
Step-by-step explanation:
When adding a whole number to a number with two digits after the decimal point, the sum should have 1 digit after the decimal point. This is because the number with two digits after the decimal point is more precise and has a smaller decimal place value. By adding a whole number, which has no digits after the decimal point, the result should have only 1 digit after the decimal point to maintain the level of precision.