Lesson 8 Subtraction Algorithms (Part 1)
Let’s learn a new way to subtract.
Warm-up Number Talk: Subtraction Strategies
Find the value of each expression mentally.
Activity 1 From Drawings to an Algorithm
Jada and Kiran found the value of
Explain how Kiran’s algorithm starts.
Explain how Kiran recorded the decomposition of the ten into more ones.
Finish Kiran’s work.
Activity 2 Card Sort: Diagrams and Algorithms
Your teacher will give you a set of cards. Match each diagram with an algorithm.
Explain or show your thinking.
Here is a subtraction calculation.
Explain what the 400 above the 500 means.
Explain what the 140 above the 40 means.
Explain how the calculation works to find