Download Mathematical Expressions Notes

WARM UP
1. Do ACT Prep Passage B –
Stickleback Fish.
Start when the bell rings.
Mathematical Expressions
Units
• Numbers need units to be meaningful
– 14 ????
• grams, pounds, kilograms, tons?
Formulas
• One unit is determined by a mathematical
operation using two (or more) other units
– area = l x w
– d = m/v
– e = mc2
Formulas
• You can rearrange the equation to solve
for an unknown unit
– w = area / l
– m = dv
– m = e / c2
Practice
Factor – Label Method
• Allows you to convert from one unit to
another
– Miles to feet
– m to km
Factor – Label Method
• Need a conversion factor that represents
how the two units are related
– 1 mile = 5,280 feet
– 1 km = 1,000 m
Factor – Label Method
• Conversion Process
1. Write known number, with unit, as a
fraction
244 rolls
1
Factor – Label Method
• Conversion Process
1. ….
2. Write conversion factor as a fraction,
with desired unit on top
244 rolls
1
1 dozen rolls
12 rolls
Factor – Label Method
• Conversion Process
1. …
2. …
3. Multiply the fractions and cancel the
units
1. 244 rolls 1 dozen rolls
x
1
12 rolls
Practice
WRAP UP
• Give one reason units are important.
• Use the factor-label method to convert 19
quarts into gallons.