# 101 and you're out (2-digit-addition)

A thinking mathematically practice focused on developing flexible additive strategies, including place value and renaming numbers for Stages 1 and 2.

## Syllabus

Syllabus outcomes and content descriptors from Mathematics K–10 Syllabus (2022) © NSW Education Standards Authority (NESA) for and on behalf of the Crown in right of the State of New South Wales, 2024.

Adapted from Win Win Games by Marilyn Burns.

## Outcomes

- MAO-WM-01
- MA1-CSQ-01
- MAO-WM-01

- MA2-AR-01
- MA2-AR-02

## Collect resources

You will need:

- dice or numeral cards 1–6
- pencils or markers
- something to write on.

## 101 and you're out!

Watch video 101 and you're out! (4:36).

#### Michelle

Good afternoon, everybody. Hi Barbara.

#### Barbara

Hi Michelle.

#### Michelle

How you going?

#### Barbara

I'm good. I'm ready to win.

#### Michelle

Yeah, I was gonna say that alright, well to win we're playing a new game today called 101 and bust.

#### Barbara

OK.

#### Michelle

So, the goal is to get 100 or as close to 100 as possible without going over.

#### Barbara

OK.

#### Michelle

We need this dice, and we need a table to help us record our thinking. So, we need to draw our table as a 7 by 4 table.

[Screen shows large piece of white paper, and a 6-sided dice. Michelle and Barbara each draw a rectangle.]

And then I'll usually just halve it.

#### Barbara

That's good to make 4 columns.

#### Michelle

And then I halve the half because when you halve one-half of one-half is one-quarter.

[Michelle and Barbara draw a vertical line down the middle of their rectangles, then another vertical line in each half to make 4 columns.]

#### Barbara

OK.

#### Michelle

And then we need 7 rows.

#### Barbara

How do we do that? Just try our best?

[They draw a horizontal line about a centimetre from the top of the rectangle to make a row.]

#### Michelle

Yeah, well, I usually, because if we got one section already done, you've now need 6 equal pieces, and I can relate 6 to halves and thirds.

[They then draw a horizontal line through the middle of their rectangles.]

So, if I halve it like you just did and then I can just sort of get my eye in and third each section. Yeah.

[They then draw some dashes to mark out a third and then draw another 2 horizontal lines across each half to make 6 rows and a total of 28 boxes within each rectangle.]

#### Barbara

OK.

#### Michelle

Alright so up here is, we need the labels 10s, then ones, then number and total.

[They write the 4 headings in the boxes at the top of each column. “Tens” is written in the first box, “ones” in the second box, “number” in the third box and “total” in the fourth box across the first row.]

#### Barbara

Ok.

#### Michelle

And we can roll one dice. Or we can roll 2 and we each have one that we use but we will just share this one today and we roll the dice.

[Dice is rolled, and the number 4 is displayed.]

And we have to decide with the 4 if we want the 4 to be worth 4 tens which we would then rename as 40 or 4ones which we would call 4.

[Michelle points to the tens column then the ones column.]

So, for me I think I'm going to call it 4 tens. So, I would record it like this, I've got 4 tens, the numbers’ 40 and so far, my total is 40 because 0 + 40 is 40.

[Michelle writes 4 in the ‘tens’ column, 40 in the ‘number’ column and 40 in the ‘total’ column of the second row.]

#### Barbara

I think I'm going to do the same as you.

[Barbara writes 4 in the ‘tens’ column, 40 in the ‘number’ column and 40 in the ‘total’ column of the second row. She then rolls the dice and the number 4 is displayed again.]

#### Michelle

OK.

#### Barbara

Ok. Ok.

#### Michelle

Um.

#### Barbara

I think I might do this one also as 4 tens.

[Barbara writes 4 in the ‘tens’ column, 40 in the ‘number’ column and 80 in the ‘total’ column of the third row.]

#### Michelle

Ok, I'm gonna do it as 4 ones. And so, my 4 ones and my total now is 4 tens and 4 ones which we would rename is 44.

[Michelle writes 4 in the ‘ones’ column, 4 in the ‘number’ column and 44 in the ‘total’ column of the third row.]

#### Barbara

Ok.

#### Michelle

It's my roll.

[Michelle rolls the dice and the number 4 is displayed again.]

#### Barbara

I'm sorry.

#### Michelle

That's alright. And a four.

#### Barbara

That one I will definitely do as 4 ones.

[Barbara writes 4 in the ‘ones’ column, 4 in the ‘number’ column and 84 in the ‘total’ column of the fourth row.]

#### Michelle

Umm. I'm going to do 4 ones also. So, 44 and 4 more for me is 48.

[Michelle writes 4 in the ‘ones’ column, 4 in the ‘number’ column and 48 in the ‘total’ column of the fourth row.]

#### Barbara

80 and 4 more for me is 84.

#### Michelle

Ok.

#### Barbara

OK, so I think now I need to do most of these as ones because I'm quite close to one hundred.

[Barbara rolls the dice and the number 3 is displayed.]

#### Michelle

Yeah, because if you had 3 tens more than 8 tens.

[Michelle points to the dice indicating 3.]

#### Barbara

I would bust.

#### Michelle

That would be 11 tens. You'd be over.

#### Barbara

I'd be over.

[Barbara writes 3 in the ‘ones’ column, 3 in the ‘number’ column and 87 in the ‘total’ column of the fifth row.]

#### Michelle

But I'm going use tens, so I'm going to say 3 tens which is 30, oops, that's right, and 4 tens and 3 tens of 7 tens and 8 more is called 78.

[Michelle writes 3 in the 'tens’ column, 30 in the ‘number’ column and 78 in the ‘total’ column of the fifth row.]

#### Barbara

Ok, 84 and 3 more is 87. Ok, we're pretty close now.

#### Michelle

Whoo, it's close.

[Michelle rolls the dice and the number 5 is displayed].

#### Barbara

Ones. Definitely ones.

#### Michelle

Um, 5.

#### Barbara

And 87, three more for 90 and then 2 more so I've 92.

[Barbara writes 5 in the 'ones’ column, 5 in the ‘number’ column and 92 in the ‘total’ column of the sixth row.]

#### Michelle

I have 83 because I needed 2 more to get to 80 and then three more makes 83.

[Michelle writes 5 in the 'ones’ column, 5 in the ‘number’ column and 83 in the ‘total’ column of the sixth row.]

#### Barbara

Oh, ok.

#### Michelle

So, I don't think either of us can get exactly 100 now.

#### Barbara

No.

#### Michelle

Because you would need 8 and the dice doesn't go that far, and I need 17.

[Michelle points to Barbara’s total of 92 and then to the dice, she then points to her total with only one row left to play.]

#### Barbara

I actually think I will win.

#### Michelle

Well, I could win though, because if it rolls one 10, I get 83 and you get 93. I can't win, we can tie.

Come on tie.

[Michelle points to the totals in her box and then Barbara’s box, picks up and rolls the dice which displays the number 5.]

#### Barbara

Oh ok.

#### Michelle

A 5.

#### Barbara

Well, I'm definitely 5 ones, which is 5 and now I've got to 97.

[Barbara writes 5 in the 'ones’ column, 5 in the ‘number’ column and 97 in the ‘total’ column of the last row. Michelle writes 5 in the 'ones’ column, 5 in the ‘number’ column and 88 in the ‘total’ column of the last row.]

#### Michelle

So, you're the closest. Congratulations, you're the winner.

#### Barbara

Thank you very much.

#### Michelle

But let's play again, best out of three?

#### Barbara

Ok, deal.

#### Michelle

Over to you mathematicians?

[End of transcript]

### Instructions

- Make a game board by drawing a 6 x 4 table
- Label the first column as ‘tens’, the second column as ‘ones’, the third column as number and fourth column as total
- Each time you roll the dice, you have to decide whether the number is representing ‘ones’ or ‘tens’
- For example, if I roll a 3, I could use it as 3 ones (3) or 3 tens (which we rename as 30).
- If you choose to use your 3 as 3 ones, record the number in the ones column
- If you choose to use your 3 as 3 tens (30), record your number in the left column

- Continue to play for six rolls
- Once you write a number, you can’t change it
- The winner is the player with the sum that is closest to 100 without going over!
- Draw up 4 new game boards. Using the same numbers you rolled, use the game boards to get closer to 100 than you did in your first game
- Play again with someone at home.

### Other ways to play

- Increase the challenge by using numbers from 0–9. You can also use playing cards, make cards or make a spinner at home
- Roll the dice 4 times and only use four lines on the game board

### Discuss

- Did you get closer to 100 on your second go with the same numbers?
- Why do you think that was?
- What advice would you give to someone playing this game for the first time?