One of the most common questions we are asked is how our library of digital content supports the Common Core. The easy answer is that our entire library has been aligned to the Common Core standards, so teachers can find resources related to each standard. The more complex answer is that there are many pieces of content that can be used in flexible ways to support each individual standard, and it is up to teachers to choose the content that best supports their lesson and their students.
Here are five pieces of digital content a teacher might choose from our library to support and enhance the teaching of Common Core Math Standard 5.NBT.B.7: Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.
Subtracting Decimals with Base Ten Blocks
You could use this virtual manipulative with students either on laptops/tablets/Chromebooks or using real manipulatives and spend time using the base ten blocks to develop the concept of regrouping to add and subtract decimals.
Subtracting Decimals on a Number Line
You could give your students decimals to add and subtract via mental math and use the number line to demonstrate counting up and counting back strategies as the students share them.
You could use this activity as a center activity because it requires the students to use their number sense and strategies to determine what decimals will yield the greatest difference.
You could use this animation to review the traditional algorithm after the students had come up with it on their own, but I wouldn’t have them just sit and watch the animation. I would use it on my SMART Board and pause at points and question the students. Why do you have to line up the decimal points? Why is it important to have numbers in the correct place values? What is the relationship between a number and the number to its right and left? I would have the kids evaluate if the steps given are a good method or if they would add steps or remove steps. (You must be a StarrMatica member and be logged in to access this resource.)
At some point, I would use the open response test as formative assessment to see which students are able to add and subtract decimals and which need more assistance. (You must be a StarrMatica member and be logged in to access this resource.)
