Strap yourself in and get ready for the wild ride that is… 4th grade addition and subtraction! 4th grade is the first year students are expected to become proficient with the standard algorithm for addition and subtraction. And when you’re working with numbers with up to 7 places, the standard algorithm really makes sense. But don’t worry, students will build on their work with place value by exploring rounding for estimation, composing to make a larger unit, and decomposing to make 10 smaller units. Then, just for fun, I’ve included 2 robust lessons working with multiple-step – and multiple operation – word problems. Let’s go!
4th Grade Unit 3 Mini-Units
- Mini-Unit 1: Adding Numbers to 1 Million
- Mini-Unit 2: Subtracting Numbers to 1 Million
- Mini-Unit 3: Adding & Subtracting Decimals
Mini-Unit 1: Adding Numbers to 1 Million
Even though students have already worked with place value in multi-digit numbers, adding takes place value skills one step farther. Students will begin this unit and mini-unit using place value discs to build models of numbers, manually combining each place’s 2 addends to find a sum. Along the way, they will sometimes have more than 9 units in a place, and need to trade 10 units for one of the next unit up. Students then work with adding using some of our old favorites from 3rd grade. While these strategies may be easy, students will find they take a lot of time & space…leaving them with more opportunities to make mistakes. Just in time, the standard algorithm is introduced and practiced to perfection. Throughout these lessons, students explore different ways to estimate sums, looking for a combination of ease and accuracy to provide themselves with an estimate smaller than a ballpark. To wrap up the Mini-Unit, students will go through a rigorous lesson working with multi-step word problems involving comparative relationships, addition, multiplication, & division.
Mini-Unit 2: Subtracting Numbers to 1 Million
Mini-Unit 2 follows the structure of Mini-Unit 1, but we all know subtraction is very different from addition – and it can be much more challenging! That’s ok, because students will spend an entire lesson using place value discs and crossing out or taking away to subtract. They will experience manually trading larger units for 10 smaller units when needed, as well as trading to subtract across zeros. Throughout the Mini-Unit, students will continue to make and evaluate estimated differences to further develop their estimation skills.
Subtraction with previously loved strategies is even more challenging than addition! The combination of decomposing and so many steps makes it challenging to say the least. After some experience with these strategies, once again the standard algorithm saves the day. Always tied to place value understanding, subtracting from numbers up to and including 1 million is demystified for your mathematicians. Included with this Mini-Unit is the added step of adding a difference and subtrahend to make sure they equal the minuend – more practice adding, and an excellent strategy for student to check their own work. Mini-Unit 2 also wraps up with multi-step word problems involving up to 4 operations. This lesson is heavy on comparative subtraction, but include plenty of twists and turns for students to really stretch their mathematical legs.
Mini-Unit 3: Adding & Subtracting Decimals
The Texas Essential Knowledge Standards for 4th grade include adding and subtracting decimals. While Common Core generally covers this skill in 5th grade, I appreciate how this Mini-Unit builds upon the decimal place value concepts learned earlier. This mini-unit treats decimals as just an extension for the place value mat, to be added and subtracted like any other multi-digit number. This Mini-Unit focuses on hands-on strategies including decomposing and composing to regroup and a heavy focus on money, which is such a logical (and motivating!) way to explore decimals.
Digital Guided Math Activities Included!
Each component of the 4th Grade Guided Math Curriculum comes in printable and digital versions to maximize your flexibility teaching these important concepts. YOU can choose which version of each lesson component should be used – and when – for your diverse learners.