Basic Subtraction - CVI Lesson and Tips

Photo of Sadie intently looking at math app on an iPad with number line. Text, "CVI Math lesson: subtraction"

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Photo of Sadie intently looking at math app on an iPad with number line. Text, "CVI Math lesson: subtraction"

This lesson is a jumping off point to become a unit done in days, weeks, years of learning however necessary. Never take a lesson and end it, keep it going. Once you master 0 to 5 you keep going up to 10 and so on. 

Objective

The student will use basic subtraction from 0 to 5. 

Pre-assessment

  • What does the child know?
  • Have they shown competence in addition 1-5?
  • Can they show you what a number means by using manipulatives? What do I want them to learn?
  • What skills are required for them to achieve this goal?
  • What adaptations must be in place for optimal learning? 

Materials

  • Lakeshore Flashcards
  • 100s number board just for exposure
  • Black background for table, I use black cardstock
  • solid colored sticky notes
  • white board
  • variety of manipulatives after they have mastered to increase novelty -Number line for exposure, we will teach another lesson in future 

Large print "4+7=11" flashcard above the number line with moveable arrow on a black background.

Photo of Sadie intently looking at Counting app (iPad screen is perpendicular to table) with number line on table.

Great FREE app I found for Sadie in her first grade year

I spent a dollar and got the math app and we love it. Great! For basic math and very CVI friendly!
WHY I like this app for + and -, the crows are easy to count, and they mix addition and subtraction but it is easy to switch since there is auditory input and the addition problem is “day time” counting crows and the subtraction problem is “night time” counting crows since they leave. 

Learning to Count app

screenshot of Learning to Count app with image of cartoon black bird.

Great App for Pre-K and still use in 1st grade

Starfall 

Procedure

  • Teacher will introduce numbers by placing flashcard numbers1-5 in order
  • Remind student of basic addition procedures and then ask...”what happens if we “take away” numbers?
  • I have 5 circles and I “takeaway” 2 ... how many do I have left? 5-2= What? Let’s count!

Small personal whiteboard with handwritten 3-1=2 3 shells on a black background with lighted handheld magnifier.

We used the whiteboard a lot and after “getting the hang of subtraction, I purposefully introduced novelty and used small shells on a black background with a lit magnifier. This is NOT used initially, this is done to enhance the lesson. 

  • Use the same manipulatives and materials you used for addition this will make learning so much easier 
  • Play a game that is CVI friendly 
  • Starfall has a free version forl earning and Sadie and I Iove it. 

They have great reinforcement learning activities. 

Ongoing

I like to incorporate subtraction at home during meal and snack time, since we are eating we are “taking away”/subtracting so it is an easy time to do this. Example: I have 10 goldfish, if I eat 2 how many do I have left - 10 “take away” 2 equals...LET’S Count and see! 

More Math Ideas

photo taken at school with Sadie using number line and with APH's hundreds chart in front of her.

APH hundred board, we let all the students in her class use it and we also had one just her own that she took home. Yes, we get to count to a hundred, over and over again. :) This helps our CVI kids understand that numbers go on FOREVER. Find a peer who is good at it and get them to help. Then this is the time to introduce skip counting: 10, 20 30, 40... 

$15
Number line we ordered 

Tips

  • Make sure you have the child point and look while counting. This is hard for our CVI kids. If it’s too much and a break doesn’t help, then change it while making sure they touch while counting.
  • Manupulatives need to be easy to see and they don’t move around too much. If they do, kids will recount or lose count. 

Screenshot of Amazon item, Hand2Mind number paths (number line with moveable arrow) for $19.24

I started using 2 inch sticky notes on black cardstock so they stay in place as counting manipulatives. 

Flashcard with 1+8= and 2" pink sticky note in first column and 8 2" yellow sticky notes in second column.

  • Consistency is key like using the same language each time
  • Always start counting left to right
  • Play the same games with numbers till there is success and start small 1-5
  • Don’t keep changing flashcards, the look of numbers, fonts, etc. until the student is really good at recognizing numbers: novelty will confuse -Zero is a hard concept, don’t be surprised if they are confused by this meaning “nothing”

Assessment

With CVI the introduction of subtraction will be novel but should go quicker with basic addition mastered. Use the same flashcards, manipulatives, and language. 

I’m not a tester, I assess. A test means there can be failure. There is no failure for us. 

The child has achieved this learning activity when they can “tell” verbally or by showing you correct answers of basic subtraction with their appropriate adaptations of course! 

Resources

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