Using Fancy Forms of One

Multiplicative Identity Property = multiplying
by one does not change the value of a number



5·1=5
x·1=x
Multiplying by a FFOO makes your value look
different, while still having the exact same
value
FFOO’s allow conversions between systems
1. Create a FFOO comparing the units you have to
the units you want.

FFOO = Fancy Form of One
2. Arrange the FFOO so that the units will cross
cancel.
starting unit
same unit
3. Multiply straight across.
4. Simplify your answer
My textbook is 18.3 cm long. How many
millimeters is this?
 Starting Unit: cm
 Ending Unit: mm
 Conversion Factor: 1 cm = 10 mm
18.3 cm
1
10 mm
1 cm
= (18.3) x (10) = 183 mm
James walks 2.3 km to school. How many meters
does he walk?
 Starting Unit: km
 Ending Unit: m
 Conversion Factor: 1 km = 1000 m
2.3 km
1
1000 m
1 km
= (2.3) x (1000) = 2300 m
How many liters are in 355.5 milliliters of water?
 Starting Unit: mL
 Ending Unit: L
 Conversion Factor: 1 L = 1000 mL
355.5 mL
1
1L
= 355.5 L = .3555 L
1000 mL 1000
The distance to Disneyland is 26.2 km. How many
centimeters is this?
 Starting Unit: km
 Ending Unit: cm
 Conversion Factor: ?
The distance to Disneyland is 26.2 km. How many
centimeters is this?
 Starting Unit: km
 Ending Unit: cm
 Conversion Factor: 1 km = 100,000 cm
26.2 km
1
100,000 cm
1 km
= (26.2) x (100,000) =
2,620,000 cm