# 10 Minus - Roll a Number

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## Objective

SWBAT construct and solve subtraction from 10 problems by rolling a number dice and subtracting from a given 10.

#### Big Idea

Preparing kindergartners for first grade is essential. So while fluency in subtracting from ten is not required (fluency to five is), knowing how to add and subtract within ten is expected.

## Daily Calendar & Counting Review

15 minutes

Each day we begin our math block with an interactive online calendar followed by counting songs and videos.

Calendar Time:

We do calendar on Starfall every afternoon.  This website has free reading and math resources for primary teachers. It also has a  “more” option that requires paying a yearly fee. The calendar use is free. A detailed description of Daily Calendar math is included in the resources.

Counting with online sources: Today we did counting practice to reinforce the counting skills. We watched two to three number recognition 0-10 videos (one to two minutes each) because some of my students students were still struggling with identifying numbers correctly in random order. We watched"Shawn the Train" and counted objects with him to refresh our memories on how to count objects to ten and to reinforce one to one counting. Since we have started the second quarter of the school year, we added to today's counting practice: counting to 20 forward and backcounting by tens to 100 and counting to 100by ones to get a jump on our end of the year goals.

## Direct Instruction

10 minutes

I open the lesson by teaching the kids a subtraction song online called, When You Subtract with a Pirate by Harry Kindergarten. The song (video) gets them excited about the lesson while helping them to remember the key points of subtraction.

We then do a quick review of subtraction fluency to five using our fingers. We hold up five fingers and put down the number necessary as quickly as we can to find the difference once I say the subtraction problem:

I say 5 minus 3 and the kids put down 3 fingers as fast as they can. They all yell out 2 within seconds of me stating the problem. We do this for several rounds.

Once the kids are warmed up, I introduce the concept for the day. I use pattern squares to demonstrate what they will be doing. I put ten squares under the doc cam in a straight line. I use only one color so it imitates what they will seeing on the game board.

I roll the dice and I state the number I roll. I remove that number of squares from the row of ten. I record the subtraction problem on whiteboard and hold it up. I then finish it by writing the difference and reading the complete number sentence (10-4=6).

I do this for a few rounds. I allow the kids to chime in near the end. They start telling me what to do as I go. This allows them to understand the steps in the game.

## Guided Instruction

10 minutes

I begin the guided practice by placing the actual game board under the doc cam. The guided practice should always be an authentic demonstration of exactly what the kids will be doing. Kindergartners struggle to transfer information from abstract to concrete and vice versa. Authentic demonstrations prevent confusion.

I roll the dice and state the number I roll (in this case three). I then cross out that number of squares from the first line of the game board. I record the subtraction problem on the first number sentence line under the first row of boxes as I say it aloud:

10 - 3 = I count the number of boxes left in the row) 7. I repeat, 10 - 3 = 7.

I do this for a few more rounds as the kids count it with me.

I have the kids go to their tables while the helper of the day passes out the game boards (they are in plastic sleeve protectors), wipes and dry erase markers to each team of students.

I walk them through the first two rounds. The game boards are double sided so they have plenty more to do on their own.

As long as I don't see any major concerns (kids not having a clue what to do), I allow them to begin playing with their partners independently.

Partners are strategically chosen. Partners are assigned with great care in mind. I partner kids according to ability levels. See the demo video below to see how I partner and/or group kids.

## Independent Practice

15 minutes

As the kids play the game independently, I roam the room looking for any students who might be struggling or are not at all grasping the concept or process of subtraction.

If I encounter anyone having severe problems, I pull those teams to the floor and continue with guided practice until they are able to tell me the steps without my assistance. I release the game back to them very slowly and I observe their play for a few rounds before I return to roaming.

Once I am able to spend my time roaming freely, I walk around the room asking kids to explain what they are doing how they are dong it (MP3). Doing this helps to solidify the concept of subtraction in their minds.

## Closure

5 minutes

I gather the kids back together on the floor. I ask them to share what they learned and if they have any ideas to share that could make the experience better.

I pull names for kids to share randomly from a jar of name sticks. This prevents subconscious bias in choosing kids to answer questions. As teachers, we often call on those we know are capable more than the others without being aware that we are doing so. Pulling the names randomly removes that possibility.

One suggestion that I have received is playing with ten pattern tiles first (squares) and a cup to put the subtracted squares into rather than starting with the game board.

## Exit Ticket

5 minutes

The exit ticket is a page that has four subtracting from 10 problems that the kids must solve as a ticket out the door to their special area classes.

As I collect the papers I place them in three piles:

Meets - solved correctly, correct number of squares crossed out

Approaches - correct representation, but inaccurate answer (most likely a miscount)

Falls Far Below - representation and solution incorrect (needs small group and/or one on one instruction)