# Lesson: Subtracting Whole Numbers (Lesson 1)

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### Lesson Objective

Students will subtract 2 digit numbers with and without regroup

### Lesson Plan

Do Now:
Circle the number that is bigger.
1. 66 or 67
2.  536 or 456
3.  773 or  373
4. 2,309 or 2,903
5.21,843 or 2,143

Opening:
Discuss the "Do Now".

Direct Instruction:

State the objective. Direct students attention to the following  problem written on the board:  Edgar had 43 Bakugan cards.  He gives Sabrina 19 cards.  How many Bakugan cards does Edgar have left?   Read the problem aloud.  Model setting this problem up vertically. Think aloud while solving.  First, decide whether to regroup.  Explicitly tell students that regrouping renaming a number.  If we renamed 43.  It would be 3 tens 13 ones.  Then, subtract the ones.  Record the 4.  Next, subtract the tens.  Record the 2 in the tens place. Circle the answer 24.  Explicitly tell students that Edgar now has 24 Bakugan card.

Guided Practice:

Allow for student input when solving: 97-36; 44-27, and 83-15.  After each problem ask:  Did we have to regroup?  If so in what column?  How did you know when to regroup.

Independent Practice:

Complete worksheet

Closing:

Exit Card:  What the difference between 67 and 39?  Did you need to regroup?  How do you know when you need to regroup?

### Lesson Resources

 IP Subtraction lesson 1   Classwork 1,094