1. Ratio
Leslie Paytes
2009

2. Ratio*- a comparison of two quantities using division
# of pennies =
# of nickles =
Count the coins to compare the number of 
pennies to the number of nickles.
*(The word ratio comes from the Latin word ratus which means 
"calculation." In the middle ages the word ratio was used to mean 
"computation.")

3. Compare the number of pennies to nickles
There are three different ways to write a ratio when 
comparing a part to a part...
Pull
Use a colon between the two 
numbers 5:3
Pull
using the word "to"
between the two numbers
5 to 3
All three are read
5 to 3
Pull
as a fraction 5/3
Move coins for more info!

4. Suppose you wanted to compare 
the number of boys to girls in a 
class that had 15 boys and 13 
girls. The first quantity in this case 
the boys is always written first
Move the 
Mathman to reveal 
the answer
15/13
15 to 13
15:13

5. Notice with the same numbers 15 
boys and 13 girls, a comparision of 
girls to boys would yield an entirely 
different answer
Move the 
Mathman to reveal 
the answer
13/15
13 to 15
13:15

6. Suppose you wanted to compare 
the number of boys to the total number of students in a class that 
had 15 boys and 13 girls. The first 
quantity in this case the boys is 
always written first.
Hint!
add numbers
to find total
Move Mathman to 
reveal an 
additional way to 
write ratios
15/28
15 to 28
15:28
15 out of 28