Tina Stowe 2nd Grade Wooden Elementary Red Oak, Texas Subtraction Problem Solving Day 1: Take away 2-digit and 3- digit subtraction without regrouping Tina Stowe 2nd Grade Wooden Elementary Red Oak, Texas

1. Mrs. Carson’s room has 27 chairs. Mrs. Black borrowed 12 of Mrs 1. Mrs. Carson’s room has 27 chairs. Mrs. Black borrowed 12 of Mrs. Carson’s chairs.  How many chairs are in Mrs. Carson’s room now? Use your concrete objects to solve the problem first. Use the objects your teacher gave you to model solving this problem. Do not write anything yet.

Mrs. Carson’s room has 27 chairs. Mrs. Black borrowed 12 of Mrs Mrs. Carson’s room has 27 chairs. Mrs. Black borrowed 12 of Mrs. Carson’s chairs.  How many chairs are in Mrs. Carson’s room now? Pictorial Number Sentence Number Line Mental Math Strategy- Basic Math Facts

27 - 12 = 15 Mental Math Strategy- 5 ones 1 tens You can use your knowledge of basic math facts to help you solve this problem. Write this on your paper in the box labeled Mental math. 27 - 12 = 15 5 ones 1 tens

2. There were 44 people on a train 2. There were 44 people on a train. At the first stop, 38 people got off. How many people are still on the train? Use the objects your teacher gave you to model solving this problem. Do not write anything yet.

2. There were 44 people on a train 2. There were 44 people on a train. At the first stop, 38 people got off. How many people are still on the train? Pictorial Number Sentence Number Line Mental Math Strategy- Compatible Numbers

44 - 38 - Mental Math Strategy- 46 40 = 6 +2 +2 You can use compatible numbers (friendly) to help you solve this problem. Write this on your paper in the box labeled Mental math. +2 +2 You can add 2 to 44 as long as you also add 2 to 38. 44 - 38 - 46 40 = 6

3. There are 163 basketball games on Pat’s schedule 3. There are 163 basketball games on Pat’s schedule.  He has already played 147 games. How many basketball games does he have left to play? Use the objects your teacher gave you to model solving this problem. Do not write anything yet.

3. There are 163 basketball games on Pat’s schedule 3. There are 163 basketball games on Pat’s schedule.  He has already played 147 games. How many basketball games does he have left to play? Pictorial Number Sentence Number Line Mental Math Strategy- Counting up

163 - 147 = 16 163 160 147 150 Mental Math Strategy- Counting up Which number is the smallest? Your difference is 16. 163 - 147 = 16 +3 +10 +3 163 147 150 160 Start at 147. What is the closest ten to 147? How much did I have to add to 147 to get to 163? Now, you can count by tens! How much would we need to add to 147 to get to 150?

4. A farmer planted 176 red roses. 153 of the roses die 4. A farmer planted 176 red roses. 153 of the roses die. How many roses does the farmer have now? Use the objects your teacher gave you to model solving this problem. Do not write anything yet.

4. A farmer planted 176 red roses. 153 of the roses die 4. A farmer planted 176 red roses. 153 of the roses die. How many roses does the farmer have now? Pictorial Number Sentence Number Line Mental Math Strategy- Partial Differences

176 - 153 23 100 + 70 + 6 - 100 + 50 + 3 20 + 3 Mental Math Strategy- Partial Differences using expanded form Mental Math Strategy- 176 - 153 100 + 70 + 6 Your difference is 23. - 100 + 50 + 3 23 20 + 3