Units of Weight

WEIGHT

How Heavy is it?

There are 2 main units of customary weight:

Pounds Ounces

Ounces are used to weigh light things

A letter is about an ounce.

Pounds are used to weigh heavy things

Your Open Court book weighs about a pound.

The abbreviation for pound is lb.

The baby weighs

15 lbs.

The abbreviation for ounce is oz.

The pencil weighs about

5 oz.

Conversions

1 lb = 16 oz.

One way to remember is that lb sort of looks like 16!

lb 16

Tom had 4 lbs. of fruit. Sam had 36 oz. of fruit. Who had more?

Step 1: What do I know?

I know that they both need to be the same unit because I can’t compare different units.

Step 2: Choose the lower unit and convert.

Since there are oz and pounds, ounces are the smaller unit. I will convert to ounces.

Since I know that 1 lb = 16 oz, I can make a table.

pounds 1

ounces 16

pounds 1 2 3 4

ounces 16 32 48 64

4 pounds is equal to 64 oz.

Tom had 4 lbs. of fruit. Sam had 36 oz.

of fruit. Who had more?

Since 4 pounds = 64 oz, then Tom had more, because 64 oz > 36 oz.

I can also DRAW A PICTURE to convert measurement.

Since 16 oz is one pound, then…

16 oz 16 oz 16 oz 16 oz

16 + 16 + 16 + 16 = 64 OR 4 x 16 = 64

Metric Measurements

Gram—used for light items

A paper clip is about a gram.

Kilogram—used for bigger things

Your math book is about a kilogram.

Abbreviations

Gram g

Kilograms kg

Remember…1,000 g = 1 kg

Conversions

Mary needed 5,000 g of flour for the recipe. She had a bag of 4 kg. Does she have enough?

Convert to lowest measure… Grams!

Since 1 kg = 1,000 g, then 4 kg = 4,000g

1,000 g 1,000 g 1,000 g

1,000 g

Draw a Picture!

So…she does not have enough. She only has 4,000 kg!

Mary needed 5,000 g of flour for the recipe. She had a bag of 4 kg. Does she have enough?