Lesson: Bridge Method T
The Bridge Method
a method of converting units using cancellation
The Bridge Method
to use the bridge method...
to use the bridge method...

you have to have...

to use the bridge method...

you have to have...

Unit Conversion Factors
to use the bridge method...

you have to have...

Unit Conversion Factors
Like these

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

You also have to have something to be converted

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in
Like this
You also have to have something to be converted

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

Conversion problem

?
5 ft = _____ in
Which is which?
Unit conversion Factors
?

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

1. Draw the bridge

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

1. Draw the bridge
the bridge will look like a 'plus' sign

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

1. Draw the bridge
the bridge will look like a 'plus' sign
Like this

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

2. Write the given information in the bridge

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

2. Write the given information in the bridge
5 ft
always put it in the top left
Right here

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

Given information goes in the
Top Left
Top Right
Bottom Left
Bottom Right
5 ft = _____ in

Let's go through the steps of the bridge method

3. Find the unit conversion factor you need
5 ft

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

3. Find the unit conversion factor you need
5 ft
you need one that has the given unit

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

3. Find the unit conversion factor you need
5 ft
you need one that has the given unit
the given unit is feet

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

3. Find the unit conversion factor you need
5 ft
you need one that has the given unit

there are 2 unit conversion

 factor with feet

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

3. Find the unit conversion factor you need
5 ft
you need one that has the given unit

but since we are converting

to inches we will use the one

 with inches

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
5 ft

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft

The factor will be

written in the second

column

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft

it can either be written

like this

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft
12 in
1 ft

it can either be written

like this

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft
12 in
1 ft

or like this

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft
1 ft
12 in

or like this

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft
1 ft
12 in

but the units must

cancel

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft
1 ft
12 in

but the units must

cancel

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft
1 ft
12 in

but the units must

cancel

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

Since feet is in the top
5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
be sure that the units cancel
5 ft
1 ft
12 in

but the units must

cancel

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

4. Write the unit conversion factor in the bridge
Feet must also be in the bottom
be sure that the units cancel
5 ft
1 ft
12 in

but the units must

cancel

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

5. Cancel the units
5 ft
1 ft
12 in

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

5. Cancel the units
5 ft
1 ft
12 in

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

5. Cancel the units
5 ft
1 ft
12 in

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

6. Then do that math
5 ft
1 ft
12 in

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

Multiply numbers in the top, divide bottom numbers
6. Then do that math
5 ft
1 ft
12 in

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

Multiply numbers in the top, divide bottom numbers
6. Then do that math
5 ft
1 ft
12 in
5

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

Multiply numbers in the top, divide bottom numbers
6. Then do that math
5 ft
1 ft
12 in
5 x 12

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

Multiply numbers in the top, divide bottom numbers
6. Then do that math
5 ft
1 ft
12 in
5 x 12 ÷ 1

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

Multiply numbers in the top, divide bottom numbers
6. Then do that math
5 ft
1 ft
12 in
5 x 12 ÷ 1 = 60

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft = _____ in

Let's go through the steps of the bridge method

The answer is 60!
5 ft
1 ft
12 in
5 x 12 ÷ 1 = 60

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

5 ft =   60  in

Let's go through the steps of the bridge method

The answer is 60!
5 ft
1 ft
12 in
5 x 12 ÷ 1 = 60

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

Let's try another one!!!

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
1. Draw bridge

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
1. Draw bridge

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft

1. Draw bridge

2. Write problem

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
30 in

1. Draw bridge

2. Write problem

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
30 in

1. Draw bridge

2. Write problem

3. Find conversion

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
30 in

1. Draw bridge

2. Write problem

3. Find conversion

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
30 in

1. Draw bridge

2. Write problem

3. Find conversion

4. Write conversion

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
30 in
12 in
1 ft

1. Draw bridge

2. Write problem

3. Find conversion

4. Write conversion

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
30 in
12 in
1 ft

1. Draw bridge

2. Write problem

3. Find conversion

4. Write conversion

5. Cancel units

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
30 in
12 in
1 ft

1. Draw bridge

2. Write problem

3. Find conversion

4. Write conversion

5. Cancel units

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
30 in
12 in
1 ft

1. Draw bridge

2. Write problem

3. Find conversion

4. Write conversion

5. Cancel units

6. Do math

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

30 in = _____ ft
30 x 1 ÷ 12 = 2.5
30 in
12 in
1 ft

1. Draw bridge

2. Write problem

3. Find conversion

4. Write conversion

5. Cancel units

6. Do math

1 ft = 12 in

3 ft = 1 yd

1 mi = 5,280 ft

What are the steps to the bridge method
What are the steps to the bridge method

1.

2.

3.

4.

5.

6.

7.
Cancel Units
?
Find Conversion
?
Write Conversion
?
Draw Bridge
?
Write Problem
?
Do Math
?
2.3 ft = ? in
2.3 ft
?
12 in
?
1 ft
?
0.78 mi = ? km
0.78 mi
?
1.61 km
?
1 mi
?
17 in = ? mm
17 in
?
2.54 cm
?
1 in
?
10 mm
?
1 cm
?
200 mm = ? cm
200 mm
?
1 cm
?
10  mm
?
30 in = ? yd
30 in
?
1 ft
?
12 in
?
1 yd
?
3 ft
?
2500 mm = ? km
2500mm
?
1000 mm
?
1 m
?
1 km
?
1000 m
?
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