Add/Subtract whole numbers & Decimals

4th Grade Math Resources for families

Big Ideas

Add and subtract whole numbers

Add and subtract decimals to the hundredths place building on models to use the standard algorithm

Add and Subtract Whole Numbers

  • Provide opportunities for your child to practice multi-digit addition. Ask him/her to look in a magazine or newspaper for numbers greater than one thousand and choose two of the numbers and to add them together, then to explain each step.
  • Let your child be the teacher. First, she’ll need to start by coming up with a word problem for you that involves subtraction. (For example: The ice cream stand sold 1,367 cones on Monday and 988 cones on Tuesday. Solve to find out how many more cones were sold on Monday than on Tuesday.) Next, she’ll need to ask you to solve the problem. Ask your child, “Is my answer reasonable? How do you know?” Then ask her to check your work to see if it’s correct.

Practice Problems:

Add and subtract decimals to the hundredths place building on models to use the standard algorithm

  • Write a challenging number with two numbers to the right of the decimal, such as 1,769,432.15. Ask your child to say the number in unit form. “Say the number using place value units starting from the millions to the thousandths place.” (Answer: 1 million, 7 hundred-thousands, 6 ten-thousands, 9 thousands, 4 hundreds, 3 tens, 2 ones, 1 tenth, 5 hundredths.)

How-To Video: Add/Subtract Decimals

Game: Adding Whole Numbers and Decimals

Game: Subtracting Decimals

Game: Decimal Number Conundrum