What you’ll learn
Add and subtract multi-digit decimals.
Key idea
Tenths combine with tenths and hundredths combine with hundredths.
Align decimal points without changing operand values; a one-sided shift is not equivalent decimal notation.
Worked example
Enter the exact value or ordered values in the format requested below.
Compute 3.30 − 0.11 exactly. Enter the decimal result.
- Use hundredths throughout: 330 − 11=319 hundredths.
- Converting back gives 3.19.
Answer: 3.19
Quick Check
Evaluate a worked attempt at add and subtract multi-digit decimals, identify the first invalid step, and provide the correction.
A student writes Step 1: operate on 3.59 and 1.41. Step 2: shift only the second operand one place, calculating 3.59 + 0.141=3.731. Locate the first invalid step and correct it.