2nd Grade Common Core Math Plans
Three Digit Add.Sub Lesson Plan Week 3
Monday, February 25 - Friday, March 1,2013 -
The student will:
1) Review the Addition Strategy of the Week – Doubles, Doubles Plus One and Two.
2) Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
Essential Question - How can we add and subtract within 1000 using strategies?
Vocabulary-
Same as 1st week
Materials
Journals
Doubles Memory Cards (Resource Box)
Squares (Resource Box)
Who Has More? (Resource Box)
Branching Blitz Worksheet and Answer Key (Resource Box)
Using Doubles Fact Cards - Addition (Resource Box) - large and small versions
Assessment Task - Addition by Partitioning 2.NBT.7 Worksheet(Resource Box)
Addition Without Regrouping Give and Take Worksheet and Answer Key (Resource Box)
It's Game Time Worksheet (Resource Box)
Riddle 12 Extra Worksheet (Resource Box)
Ladders (Resource Box)
Match ’Em Up Cards (Resource Box)
Spin and Double It (Resource Box)
Riddle 36 Worksheet (Resource Box)
3-Digit Subtraction Split (Resource Box)
Monday, February 25, 2013 -
Materials:
- Journals
- Doubles Memory Cards (Resource Box)
- Squares (Resource Box)
- Who Has More? (Resource Box)
- Branching Blitz Worksheet and Answer Key (Resource Box)
In this lesson -
1) Review the Addition Strategy of the Week – Doubles. Have students review doubles because you want them to have a quick recall of double facts. Reviewing doubles facts through whole-class or partner fact card review, doubles tasks at a math center, and revisiting doubles games will set the stage for an easy transition to using doubles. Use the Doubles Memory Cards, Squares, and/or Who Has More? (Resource Box) to review doubles.
2) Discover and be introduced to addition invented strategies (abstract) when adding within 1000. Look at notes on invented strategies for ideas (Regrouping and Not Regrouping).
TeachingStrategies:
1. Students have been using manipulatives and drawings to solve adding two 3-digit numbers without and with regrouping. Now they will discover and review invented strategies.
2. Start off reviewing 2-digit and 2-digit. Ask students how they would solve 16 + 27 without using a manipulative or a drawing. Teachers - some students may solve it the traditional way - add the ones and then add the tens. It is very important to be open to different ways (invented strategies).
3. Can students think of another way to solve this problem? If not, tell them that you are reviewing a new way called Front End Addition that they have learned before. Have students practice this strategy with you today. They may use another strategy if they want to on Tuesday.
Front End Addition or Partial Sums Algorithm - Has 2 advantages: students read from left to right and working first with the largest units yields a closer approximation earlier so you get a better estimation of your answer quickly.
16 10 + 20 = 30 6 + 7 = 13
+ 27
30
13
43
4. Practice this method with several problems. Teachers - Remember to be open to other invented strategies (see notes for more examples).
5. Now practice with adding two 3-digit numbers within 1000 using Front End Addition.
264 200 + 400 = 600 60 + 20 = 80 4 + 3 = 7
+ 423
600
80
+ 7
687
6. Can you use Front End Addition when you normally have to regroup? Yes
264 200 + 400 = 600 60 + 80 = 140 4 + 7 = 11
+ 487
600
140
+ 11
751
SummarizingStrategy:Journal-Solve 326 + 173 = _____ and 145 + 267 = _____ using the front end addition method. They need to show steps and be able to write their explanation.
Classwork/Homework: Have students complete the Branching Blitz Worksheet (Resource Box). This is Front End Addition with a different name.
Tuesday, February 26, 2013 -
Materials:
- Journal
- Doubles Memory Cards (Resource Box) – from Monday
- Using Doubles Fact Cards - Addition (Resource Box) - large & small versions
- Assessment Task - Addition by Partitioning 2.NBT.7 Worksheet (Resource Box)
In this lesson -
1) Review the Addition Strategy of the Week – Doubles Plus One.Begin a whole-class fact card practice with the facts, using a think-pair-share technique. As you show a doubles memory card, cue students to think, pair, and share the sums.
- Think: Think about the sum. Don’t raise your hand. Don’t say the answer.
- Pair: Turn and tell your partner the sum.
- Share: Raise your hand and share the sum with the class.
Begin with doubles facts, but tell students you will be adding some new fact cards. Show students 4 + 4 and have them think-pair-share. Then show 4 + 5. As students share their ideas, draw a simple diagram on the board of a row of 4 dots and a row of 5 dots right below them. Record 4 + 4 + 1. Ask students some questions to prompt their thinking:
How is this like doubles? How is it different?
Would knowing 4 + 4 help you find 4 + 5? How?
Is 4 + 5 the same as 4 + 4 plus 1 more (4 + 4 + 1)? Explain.
Show students the 5 + 5 fact card, following by the 5 + 6 fact card. Again, ask students to turn and tell a partner how the two fact cards are alike and how they are different. Draw a diagram and record 5 + 5 + 1.
Repeat for 6 + 6 and 6 + 7 and then repeat for 7 + 7 and 7 + 8.
2)Discover and be introduced to addition invented strategies (abstract) when adding within 1000. Look at notes on invented strategies for ideas.
TeachingStrategies:
1. Today review Front End Addition (Partial Sums Algorithm), but see what other strategies students want to use. Refer to your teacher notes to give you ideas if needed.
2. Solve some problems like 236 + 153 = _____ and 245 + 377 = _____. Have several students explain their strategy and practice writing their explanations. Take time doing this because it is better to do a few problems well.
SummarizingStrategy:Journal–Have students solve 145 + 173 = _____ and 305 + 262 = _____ using whatever strategy they want to. However, they need to show steps and be able to write an explanation of how they got their steps.
Classwork/Homework: Have students complete Assessment Task - Addition by Partitioning 2.NBT.7 Worksheet (Resource Box) using whatever strategy they want to. They must show their work either on the worksheet or on a piece of paper.
Wednesday, February 27, 2013 -
Materials:
- Journals
- Addition Without Regrouping Give and Take Worksheet and Key (Resource Box)
- It's Game Time Worksheet (Resource Box)
- Riddle 12 Extra Worksheet (Resource Box)
In this lesson -
1) Review the Addition Strategy of the Week – Doubles Plus One. Repeat the think-pair-share technique from Tuesday, but once students gain confidence with doubles-plus-one thinking, pose some fact cards with the addends reversed (e.g., 7 + 7, 8 + 7). Discuss how the facts are alike and different. Remind students that the order of the addends does not matter. Doubling the lower one and adding 1 will allow them to find the double-plus-one sum.
2) Discover and be introduced to addition invented strategies (abstract) when adding within 1000. Look at notes on invented strategies for ideas.
TeachingStrategies:
1. If your students like strategy #4 from your teacher notes "Use a nice number and compensate," you may want to have them practice with the worksheet called Addition Without Regrouping Give and Take (Resource Box). This is only dealing with 2-digit and 2-digit, but it is good practice on this strategy.
2. Use this day to review several strategies for adding two 3-digt numbers within 1000.
SummarizingStrategy:Journal–Have students solve 159 + 271 = _____ and 345 + 232 = _____ using whatever strategy they want to. However, they need to show steps and be able to write an explanation of how they got their steps.
Classwork/Homework: Have students solve It's Game Time Worksheet (Resource Box) using whatever strategy they want to. Remember that you want them to solve problems well (show steps and explanations) so if they only solve a few problems, that is fine. There is an extra worksheet called Riddle 12 (Resource Box) if needed for more practice.
Thursday, February 28, 2013 -
Materials:
- Journals
- Ladders (Resource Box)
- Match ’Em Up Cards (Resource Box) – 2 different pages
- Spin and Double It (Resource Box)
- Riddle 36 Worksheet (Resource Box)
In this lesson -
1) Review the Addition Strategy of the Week – Double Plus One. Have students review their doubles and doubles plus one by playing any of the following games: Ladders, Match ’Em Up Cards (2 different pages in Resource Box), Spin and Double It (Resource Box). Directions are below.
Directions on how to play games (Resource Box):
Ladders – This game provides practice with near-doubles facts and challenges students to order numbers from least to greatest. To play Ladders, two students take turns spinning a near-doubles spinner and recording the sum on a vertical number line. The sums must be recorded in order from least (bottom) to greatest (top). If a student spins a sum and does not have a place to put it on his ladder, he loses his turn. The first player to complete his ladder is the winner.
Match ‘Em Up – In Match ‘Em Up, partners spread out near-doubles math fact cards and double-plus-one math fact cards. For example, a player might match 3 + 4 to 3 + 3 + 1. Students match the cards and record their matches on the Match ‘Em Up recording sheet.
Spin and Double It – Students work with partners to explore double facts. One partner spins the 3-9 spinner to find the starting number. The other partner spins the doubles wheel to find out if they will be finding the double or double plus one. Partners then work together to write the number sentences.
2) Discover and be introduced to subtraction invented strategies (abstract) when subtracting within 1000. Look at notes on invented strategies for ideas.
TeachingStrategies:
1. Students have been using manipulatives, drawings and strategies to solve two 2-digit numbers subtraction problems without and with regrouping. Review these as needed. Remember that students may still need to use manipulatives and/or drawings to solve these problems.
2. Now they will review or discover more invented strategies. Ask students how they would solve 36 - 23 without using a manipulative or a drawing. Teachers - some students may solve it the traditional way - subtract the ones and then subtract the tens. It is very important to be open to different ways (invented strategies). Teachers - See the Teacher Notes (Resource Box) for suggested strategies.
3.Now give students some three-digit subtraction problems without trading (regrouping) and see if they can do strategy one (Left to Right or Expanded Form).
Ex:1 536 – 323 =
536 500 30 6
- 323 -300 -20 -3
200 + 10 + 3 = 213
Ex: 2 879 –1 21 =
879 800 70 9
- 121 -100 -20 -1
700 + 50 + 8 = 758
4. Be open to other strategies so see teacher notes for more ideas if needed.
5. What happens if you have a problem like this (Allow students time to think this out so do not just show them how to do it right away):
Ex: 1 373 – 146 =
373 300 70 3 need to expand again 300 + 60 + 10 + 3 = 300 + 60 + 13
- 146 -100 -40 -6 -100 -40 -6
200 + 20 + 7=227
SummarizingStrategy:Journal-Describe how you would solve this problem: Andrew's book has 328 pages. He has read 116 pages so far. How many pages does Andrew have left to read?
Classwork:Have students practice the Expanded Form Strategy or Subtracting Left to Right using the Riddle 36 Worksheet (Resource Box). They may only have time to do a few problems.
Friday, March 1, 2013 -
Materials:
- Journals
- 3-Digit Subtraction Split (Resource Box)
In this lesson -
1) Review the Addition Strategy of the Week – Doubles Plus Two. Use the think-pair-share technique form Tuesday and Wednesday. Begin with doubles facts, but tell students you will be adding some new fact cards. Show students 4 + 4 and have them think-pair-share. Then show 4 + 6. As students share their ideas, draw a simple diagram on the board of a row of 4 dots and a row of 6 dots right below them. Record 4 + 4 + 2. Ask students some questions to prompt their thinking:
How is this like doubles? How is it different?
Would knowing 4 + 4 help you find 4 + 6? How?
Is 4 + 6 the same as 4 + 4 plus 2 more (4 + 4 + 2)? Explain.
Show students the 5 + 5 fact card, following by the 5 + 7 fact card. Again, ask students to turn and tell a partner how the two fact cards are alike and how they are different. Draw a diagram and record 5 + 5 + 2.
Repeat for 6 + 6 and 6 + 8 and then repeat for 7 + 7 and 7 + 9.
2) Discover and be introduced to subtraction invented strategies (abstract) when subtracting within 1000. Look at teacher notes on invented strategies for ideas.
TeachingStrategies:
1. Review Expanded Form Strategy or Subtracting Left to Right with students using these problems:
Ex: 1 425 – 353 =
425 400 20 5 need to expand again 300 + 100 +20 + 5 = 300 + 120 + 5
-353 -300 -50 -3 -300 -50 -3
70 + 2 = 72
Ex: 2 912 – 734 =
912 900 10 2 need to expand again 800 + 100 + 10 + 2 = 800 + 100 + 12
-734 -700 -30 -4 -700 -30 -4
100 + 70 + 8 = 178
2. Do have students share if they solved these problems using other strategies.
3. Use Teacher Notes on Invented Strategies to try other strategies with students if they have not invented the strategies themselves (Counting Up or Counting Up/Then Counting Back. Strategy #3 - Partial Differences Subtraction - Do any students use this strategy?
SummarizingStrategy:Journal-Describe how you would solve this problem: The parents at Little River School are putting up a fence around the playground. They bought 452 feet of fencing. They have used 328 feet. How many feet do they have left?
Classwork: Have students work on 3-Digit Subtraction Split (Resource Box) with a partner. Students need to have paper to write the problem on and show their work.