1. Unit 5. Day 3.

2. Calculator allowed today

3. Example A: Kat was making cupcakes for fun
Example A: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 300 cupcakes for a wedding. How much will the ingredients cost? 45 18
300 ?
$ 𝑐 = $ 𝑐
= $ 𝑐 𝑥
120
$18 45 𝑐
÷45
$ 𝑐
0.4
300
÷45
300
3 0 0 . 4
0.4 × . 1 2 45
1 8 + − ∎
1 8 0 1 2 .

4. Example B: Kat was making cupcakes for fun
Example B: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 195 cupcakes for a wedding. How much will the ingredients cost? 45 18
195 ?
$ 𝑐 = $ 𝑐
= $ 𝑐 𝑥
$18 45 𝑐
÷45
$ 𝑐
0.4
195 78
÷45
195 3 2
1 9 5 . 4
0.4 × . 7 8 45
1 8 + − ∎
1 8 0 7 8 .

5. Example C: Kat was making cupcakes for fun
Example C: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 217 cupcakes for a wedding. How much will the ingredients cost? 45 18
217 ?
$ 𝑐 = $ 𝑐
= $ 𝑐 𝑥
86.8
$18 45 𝑐
÷45
$ 𝑐
0.4
217
÷45
217 2
2 1 7 . 4
0.4 × . 8 6 8 45
1 8 + − ∎
1 8 0 8 6 . 8

6. Example D: Kat was making cupcakes for fun
Example D: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 425 cupcakes for a wedding. How much will the ingredients cost?
Example E: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 85 cupcakes for a wedding. How much will the ingredients cost?
Example F: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 67 cupcakes for a wedding. How much will the ingredients cost?
It helps to model this with an equation.

8. $ 𝑐𝑢𝑝𝑐𝑎𝑘𝑒 ∙ 𝐶
𝑜𝑠𝑡 =
$0.40 1
$0.40 ∙
$0.80 𝐶
𝑜𝑠𝑡 =
$0.40 2
$1.20 ∙ 𝐶
𝑜𝑠𝑡 =
$0.40 3 ∙
$1.60 𝐶
𝑜𝑠𝑡 =
$0.40 4 ∙
$0.40𝑛
0.4 𝑛 𝐶 𝐶
𝑜𝑠𝑡 = =
$0.40 𝑛

9. Example D: Kat was making cupcakes for fun
Example D: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 425 cupcakes for a wedding. How much will the ingredients cost?
Example E: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 85 cupcakes for a wedding. How much will the ingredients cost?
Example F: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 67 cupcakes for a wedding. How much will the ingredients cost?
$ 𝑐𝑢𝑝𝑐𝑎𝑘𝑒
𝐶=0.4𝑛

10. Example D: Kat was making cupcakes for fun
Example D: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 425 cupcakes for a wedding. How much will the ingredients cost?
425
$ 𝑐𝑢𝑝𝑐𝑎𝑘𝑒
𝐶=0.4𝑛
𝐶=0.4 𝑛 𝐶 = 1 2
4 2 5
0.4 × 1 7 + ∎ 1
170 7 .

11. Example D: Kat was making cupcakes for fun
Example D: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 425 cupcakes for a wedding. How much will the ingredients cost?
Example E: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 85 cupcakes for a wedding. How much will the ingredients cost?
Example F: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 67 cupcakes for a wedding. How much will the ingredients cost?
$ 𝑐𝑢𝑝𝑐𝑎𝑘𝑒
𝐶=0.4𝑛

12. Example E: Kat was making cupcakes for fun
Example E: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 85 cupcakes for a wedding. How much will the ingredients cost? 85
$ 𝑐𝑢𝑝𝑐𝑎𝑘𝑒
𝐶=0.4𝑛
𝐶=0.4 𝑛 𝐶 = 2
8 5
0.4 × 3 4 + ∎ 34 3 4 .

13. Example F: Kat was making cupcakes for fun
Example F: Kat was making cupcakes for fun. She made 45 cupcakes and the ingredients cost her $18. Someone asked her if she would make 67 cupcakes for a wedding. How much will the ingredients cost? 67
$ 𝑐𝑢𝑝𝑐𝑎𝑘𝑒
𝐶=0.4𝑛
𝐶=0.4 𝑛 𝐶 = 2
6 7
0.4 × 2 6 8 + ∎
26.80 2 6 . 8

14. Which method do you like better? Why?
In what situations is one more efficient?