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Welcome to Subtraction! – Learn subtraction by counting back – Subtraction means taking away – If you have 5 apples and eat 2, you have 3 left. – Practice with numbers up to 20 – Start at 20, count back to find 20 – 4. – Master counting back by end of class – We’ll do fun activities to help you learn! | This slide introduces the concept of subtraction to second graders by using the counting back strategy. Subtraction is explained as the process of taking away numbers from a group, which is a relatable concept for young learners. The goal of today’s lesson is for students to be able to subtract numbers up to 20 by counting back. To achieve this, various activities and examples will be provided throughout the class. Encourage students to think of subtraction as ‘removing’ or ‘reducing’ items from a total count. Use real-life scenarios, such as having a certain number of toys and giving some away, to illustrate the concept. By the end of the class, students should feel comfortable with basic subtraction problems and understand how to count back to find the answer.

Understanding Subtraction – Subtraction means taking away – Subtracting makes numbers smaller – It’s like eating a cookie – If you have 5 cookies and eat 1, you have 4 left – Practice with real objects – Use toys or fingers to subtract from 20 | This slide introduces the concept of subtraction to second graders by relating it to a simple and relatable activity – eating cookies. The goal is to help students understand that subtraction is the process of taking away and that it results in a smaller number. Emphasize that subtraction is a part of everyday life and can be practiced with real objects for better understanding. Encourage students to use tangible items like toys or their fingers to practice subtracting numbers up to 20, reinforcing the concept through physical interaction. This tactile approach aids in solidifying the abstract concept of subtraction in young minds.

Counting Back: A Subtraction Strategy – Counting back on a number line – Imagine hopping backwards on a number line for each subtraction – Start with a number, step back to subtract – If we have 14, we hop back 3 steps to find the answer – Example: Subtract 3 from 14 – 14, hop back 1 to 13, hop back another to 12, and one more to 11 – Practice counting back together | This slide introduces the concept of counting back as a subtraction strategy for second graders. It’s important to visualize this as hopping backwards on a number line, which helps students understand that subtraction is essentially removing or ‘counting back’ from a starting number. Use the example provided to walk through the process step-by-step, ensuring that students can follow along and see how each hop represents subtracting one. Encourage the students to practice this technique with different numbers and to use their fingers or physical movements to simulate the ‘hopping back’ on an imaginary number line. This kinesthetic approach can be particularly effective for young learners.

Subtracting by Counting Back – Start with a number up to 20 – Subtract by counting back steps – Example: 10 apples minus 1 – If you have 10 and eat 1, count back to get 9 – Let’s practice counting back! – We’ll do it together: from 10…9! | This slide introduces the concept of subtraction by counting back for numbers up to 20. Begin by explaining that subtraction means taking away from a group. Use the example of having 10 apples and eating 1 to illustrate how to count back one step to find out how many are left. Emphasize that counting back is like taking steps backward. For the class activity, have students practice with different numbers, using physical objects like counters or drawings to visualize the process. Encourage them to say the numbers out loud as they count back. This will help solidify their understanding of the subtraction process.

Practice Time: Counting Back to Subtract – Try subtracting by counting back – I’ll give you a number to start – Start from the given number – Use fingers or a number line – Visual aids can help with counting – Count back to find the answer – Practice with numbers up to 20 | This slide is an interactive activity for students to practice the subtraction strategy of counting back. Begin by giving students a number less than or equal to 20 and ask them to subtract a smaller number by counting backwards. Encourage them to use their fingers or a number line as visual aids to keep track of the counting. This hands-on approach helps solidify the concept of subtraction as ‘taking away’. For example, if the starting number is 15 and they need to subtract 4, they would count back: 14, 13, 12, 11. The answer is 11. Provide several examples with different starting numbers and amounts to subtract. Rotate through the class, giving each student a chance to participate. This will help ensure that all students are engaged and understanding the concept.

Let’s Subtract Together! – Class subtraction examples – Count back together on problems – If we have 15 – 4, we start at 15 and count back 4 steps. – Use a number line to subtract – Visualize moving backwards on the number line for each count. – Observe number line subtraction – Watch as I demonstrate hopping back on the line. | This slide is designed to engage the whole class in a subtraction activity. Start by presenting a subtraction problem to the class and guide them through the process of counting back to find the answer. Use a number line drawn on the board or an interactive whiteboard if available. Encourage the students to visualize the subtraction process as hopping back on the number line. For example, if the problem is 15 – 4, you would start at 15 on the number line and count back four hops to land on 11. This visual and physical representation helps solidify the concept of subtraction as ‘taking away’. Make sure to do several examples with different starting numbers and amounts to subtract, ensuring that all students can follow along and understand the process.

Subtraction Game: Counting Back Adventure – Let’s play a subtraction game! – Roll the dice to move back – Roll a dice and move the number of spaces it shows, but backwards – Solve subtraction problems on spaces – Each space has a different subtraction problem, up to 20 – Count back to find the answers – Use counting back to solve the problems you land on | This interactive game is designed to help second graders practice subtraction by counting back, in a fun and engaging way. Set up a game board with spaces numbered from 1 to 20. Each space should have a simple subtraction problem that requires counting back. For example, if a student lands on space 15, the problem could be ’15 – 4′. The student would then count back four spaces to find the answer. Provide dice for the students to roll. Each student will take turns rolling the dice and moving their game piece the corresponding number of spaces backward on the board. When they land on a space, they must solve the subtraction problem before the next player takes their turn. This activity reinforces the concept of subtraction as ‘taking away’ and helps students visualize the process. Have several game boards available if the class size is large, so students can play in small groups. Encourage students to help each other and discuss the strategies they use to find the answers.

Class Activity: Subtraction Relay Race – Teams line up for the relay – Solve subtraction by counting back – Use fingers or number line to count back from a number up to 20 – Pass the baton after solving – First team to finish wins! | This activity is designed to make learning subtraction fun through a relay race. Divide the class into small teams and have them line up. Give the first student in each team a subtraction problem within 20. They must solve it by counting back, using their fingers or a number line for assistance. Once they answer correctly, they pass a baton (or any object that can serve as a baton) to the next team member, who then solves the next problem. The activity continues until one team has correctly completed all their problems. This game encourages teamwork, quick thinking, and the practical application of subtraction skills. Possible variations of the activity could include using flashcards, timed rounds, or incorporating obstacles for a physical challenge.

Review and Goodbye! – Reviewing subtraction by counting back – Subtraction means taking away – Like 5 apples, eat 1, left with 4 – Counting back to find answers – If you have 10 fingers, put down 2, how many are up? – Praise for today’s effort | As we wrap up today’s lesson on subtraction by counting back, it’s important to reinforce the concept that subtraction is the process of taking away from a group or number. Remind the students of the practical examples we used, such as starting with a certain number of objects and physically removing some to find the remaining amount. Encourage the students for their hard work and participation in today’s class and remind them to continue practicing at home with simple everyday items. This will help solidify their understanding and improve their subtraction skills. Great job, second graders!