## Number & Operations in Base Ten – 4th Grade

#### Use place value understanding and properties of operations to perform multi-digit arithmetic.

CCSS.Math.Content.4.NBT.B.4
Fluently add and subtract multi-digit whole numbers using the standard algorithm

Teacher Notes
The teacher needs to continue talk about and use place value in describing and justifying the processes students use to add and subtract.  Reenforcing place value by saying, "we are taking a one out of the hundreds and are regrouping into the ten's place value, and one hundred is ten tens..."   Understanding regrouping rather than just moving through the algorithm is essential.
Understanding how addition and subtraction algorithms relate to previously learned strategies and models and how using a standard algorithm is an abstract way to show the concrete concept of adding and subtracting is an important connection for students to make.

Student Knowledge Goals

I know basic subtraction facts.
I know how to add with regrouping.
I know how to subtract with regrouping.
I understand how the base ten system works.
Students should connect the standard algorithm for addition and subtraction to strategies based on place value and/or non-standard algorithms.
Students should be able to explain how and why the standard algorithm for addition and subtraction works.
I can check my answer for reasonableness.
I can add or subtract using the standard algorithm.

Vocabulary

algorithm
difference
inverse operation
regrouping
standard algorithm
subtraction
sum

Lessons
Engage NY Module 1 D-11 – Use place value understanding to fluently add multi-digit whole numbers using the standard addition algorithm and apply the algorithm to solve word problems using tape diagrams.
Engage NY Module 1 D-12 – Solve multi-step word problems using the standard addition algorithm modeled with tape diagrams and assess the reasonableness of answers using rounding.
Engage NY Module 1 E-13 - Use place value understanding to decompose to smaller units once using the standard subtraction algorithm and apply the algorithm to solve word problems using tape diagrams.
Engage NY Module 1 E-14 - Use place value understanding to decompose to smaller units up to 3 times using the standard subtraction algorithm, and apply the algorithm to solve word problems using tape diagrams.
Engage NY Module 1 E-15 - Use place value understanding to fluently decompose to smaller units multiple times in any place using the standard subtraction algorithm, and apply the algorithm to solve word problems using tape diagrams.
Engage NY Module 1 E-16 - Solve two-step word problems using the standard subtraction algorithm fluently modeled with tape diagrams and assess the reasonableness of answers using rounding.

Student Video Lessons
Study Jams - Adding & Subtracting