How to Convert Between Metric Units
A dollar bill
A single m & m
A single stick of gum
Before we can convert units, we have to understand what the units mean.
Metric units can measure weight, volume, and length.
Let's talk about weight (mass) first.
In the U.S., we measure weight in pounds and ounces.
Many other countries measure weight in milligrams, grams, and kilograms.
But, what is a gram?
Things that weigh about a gram include...
While one gram may not weigh a lot, 1000 grams can add up!
1000 grams = 1 kilogram
Things that weigh about 1 kilogram include...
A baseball bat
A liter of water
One gram = 1 M&M
One kilogram = 1000 M&M's
One liter bottle of pop
One liter of water
Half of a two-liter bottle
20 drops of water
1/5 of a teaspoon!
A king size waterbed
One liter of water
Anything that weighs about 2.2 pounds!
So think about it this way...
One milligram = 1/1000 of a M&M
Take your gram unit, and know that 1000 of it will be the weight of 1 kg, and 1/1000 of it will be the weight of one mg
Pick an item that weighs one gram...
Let's talk about volume - the amount of 3D space an item occupies
In the metric system, volume is measured by liters
One liter of space is ...
One millileter (mL) contains about the amount of space in...
One kiloliter (kL) contains about the amount of space found in...
Practice these problems:
What METRIC unit is appropriate for measuring each of the following? 1. The length of the room 2. The length of a piece of paper 3. The thickness of a finger nail 4. The weight of a cat 5. The weight of a penny 6. The weight of 10 pieces of sand 7. The space that a bottle of orange juice holds 8. The space that a swimming pool holds
Pause the video and then press play to check your answers
1. meters (m) 2. centimeters (cm) 3. millimeters (mm) 4. kilograms (kg) 5. grams (g) 6. milligrams (mg) 7. liters (l) 8. kiloliters (kL)
What is the best estimate for the following? 1.The weight of a toothpick: 1 mg, 100mg, 10g, 1 kg, 1L, 1mL, 1kL 2.The length of a doormat: 5g, 2.5kg, 100mg, 5cm, .3m, 2.5m, 30m 3.The capacity of a birdbath: 20mL, 2L, 50L, 2kL, 10g, 15kg, 30mg
1. 100mg 2. .3 m 3. 2L
How to convert between metric units
Method 1: Conversion Ratios
1000 grams 1 kilogram
Did you know you can set up conversion ratios to convert metric units?
It's easy - watch!
Convert 5.2 kilograms into grams
First, I will rewrite the number I want to convert
Then I will write a ratio of the number of units between what I was given (kg)and the final units I want (g)
Put the measurement unit that you started with, in this case, kilograms, on the bottom...
So that you can cancel out the units
Then just multiply the numbers left on top
and divide by the numbers left on the bottom (in this case 1)
The final unit will be grams because that is what is still leftover
And that's your answer!
Now, you try this one! Pause the video, solve the problem, then play the video to check your answer.
Convert 4.32 grams into milligrams
1. Write out the number you want to convert
Answer by Metric Ratios Check your work below
1000 milligrams 1 gram 2. Write the conversion ratio
3. Cancel out units
= 4320 milligrams
4. Multiply the top numbers and divide by the bottom number
Try this one: Convert 4532 milligrams into grams
1 gram 1000 milligrams
Try this one: Convert 2542 centimeters into kilometers Hint: involves multiple ratios
1 km 1000 m
1 m 100 cm
Hint: Multiply the top row first, then multiply the bottom row, and then divide those two numbers
Solve these problems
1. Convert 5.3 kg into g 2. Convert 71 m into cm 3. Convert 19 mL into L 4. Convert 12 km to mm 5. Convert 91cm in km
Pause the video to work. Click play to check your answers
1. 5300 g 2. 7100 cm 3. .019 L 4. 12,000,000 mm 5. .00091 km
Method 2: Step Ladder/King Henry
First, learn the order of metric units from largest to smallest
Some people use the prefixes to determine which is largest. For example, "kilo" means thousands "centi" means hundredths "milli" means thousandths So I would know that kilometers are larger than centimeters, which are larger than milimeters
Largest to smallest --------->
You can also use the following phrase to help you:
Units = liters, meters, or grams!!
Convert 5.2 kilometers into centimeters
How to convert step style
1. Decide if your units are getting smaller or larger
1. Our units are getting smaller
2. Determine how many steps you are moving.
1 2 3 4 5
2. Five steps
We will be moving the decimal place five steps to the right
5.2 km = 52,000cm
Now you try
Convert 256 mm into km
Pause video to work. Press play to check your answer
1. The units are getting larger (move decimal to the left) 2. Move decimal place 6 steps 3. The answer is .000256 km
Practice these problems
1. Convert 1987 mm into km 2. Convert 5.2kg into g 3. Convert 5.2 g into kg 4. Convert 82mL into L 5. Convert 34cm into hm
Pause video to work.
1. .001987 km 2. 5200 g 3. .0052 kg 4. .082 L 5. .0034 hm