EL Support Lesson
Compare & Contrast Addition Strategies
Students will be able to recognise different addition strategies.
Students will be able to compare and contrast strategies using sentence starters.
- Read aloud the content and language objectives and have students repeat them to a classmate.
Explicit Instruction/Teacher modeling(10 minutes)
- Write the following problem on the board: 455 + 249 =
- Tell students that they are going to solve this addition equation in two ways.
- The first way will involve separating the numbers into ones, tens, and hundreds, then adding each group separately. Breaking numbers up like this is called expanded notation.
- Show students how to solve the problem using expanded notation: 400 + 50 + 5 + 200 + 40 + 9. Explain how the hundreds, tens, and ones can be grouped together: 400 + 200 = 600, 50 + 40 = 90, 5 + 9 = 14. Then you can add 600 + 90 + 14To get the answer, 704.
- Explain that another way to solve this problem is by the standard algorithm, or regrouping. When you regroup, you change groups of ones to tens and tens to hundreds.
Guided practise(10 minutes)
- Show students the Three-Digit Addition Cards. Tell them that they will be sorting the cards into groups based on whether the strategy on the card is standard algorithm or expanded notation.
- Explain that today students will be comparing and contrasting addition strategies. When you Compare, you think about how things are the same. When you Contrast, you think about how things are different.
- As they sort the cards, students should use the sentence frame: "This strategy shows ____" to discuss each card with their partner.
- After sorting the cards independently, students should write down their answers to the following questions, using the sentence frames as needed:
- How many cards showed the standard algorithm? Sentence frame: "____Cards showed the standard algorithm."
- How many cards showed expanded notation? Sentence frame: "____Cards showed expanded notation."
- Did more cards show the standard algorithm or expanded notation? Sentence frame: "More cards showed ____Than ____."
- Support students to answer the questions by reminding them of the sentence frames they can use.
Group work time(15 minutes)
- Write the following problem on the board: 449 + 394 = __.
- Hand out an index card to each student. Have students work in the same pairs as they did for the previous activity.
- Tell one partner to solve the problem using the standard algorithm and one partner to solve the problem using expanded notation. Students should write their solutions on their index cards, showing as much of their work as possible.
- Have students share their work with each other, explaining how they solved the problem.
- Then have students explain their partner's strategy back to them. This gives students an opportunity to make sure they understand their partner's reasoning while practising their language skills.
- Ask students to compare and contrast the strategies that were used by thinking about what is similar and what is different.
- Listen as students compare and contast, providing them with support and sentence frame as needed. Consider rephrasing what students say so that they can have the opportunity to hear and revise their explanations.
Additional EL adaptations
- Have students work in a small teacher-led group.
- Allow students to explain their strategies using their home language before rephrasing in English.
- Have students write down the steps they used to solve their problems.
- Ask students to write a paragraph about how their strategies are similar and different.
- Ask students to share which strategy they prefer (standard algorithm or expanded notation) and why.
- Have students share their responses with the class and lead a discussion/debate about which strategy makes most sense to students.