What is 3.87 plus 0.45?

• A. 4.30
• B. 4.50
• C. 4.32
• D. 4.28

Answer: (C)

Adding decimals means lining up the decimal points so each place value—tenths and hundredths—is in the same column. Compute 3.87 plus 0.45 by adding place by place:

• Hundredths: 7 plus 5 equals 12 hundredths. Write down 2 and carry 1 to the tenths.

• Tenths: 8 plus 4 equals 12 tenths, plus the carried 1 makes 13 tenths. Write down 3 and carry 1 to the units.

• Units: 3 plus 0 plus the carried 1 equals 4.

So the sum is 4.32. The carry from the hundredths to the tenths and then to the units is what pushes the whole number up to 4.32. The other options come from misplacing the carry or not aligning the decimals correctly.