Lesson 14 — Activity 2: Mass


Getting Ready



In this activity, you will practise converting measurements of mass from imperial to metric units.

                             Read the next section to find out about what drivers of trucks must do.


Think about This:


Did you know that truck drivers must keep track of the mass of their vehicles and their loads? If they carry too much mass, it can damage roads and the vehicle’s suspension and cost the driver a fine at vehicle weigh stations located along highways.

(Adapted from K&E Studio.)

There are three main conversions when dealing with converting mass from imperial measure to metric measure. They are:

  • ounces to grams
  • pounds to kilograms
  • short tons to metric tons


To convert from ounces (oz) to grams (g), use the formula:

# of ounces x 28.35 =



For example, if you wanted to know how many grams were in 21 ounces, you would calculate it this way:

21 x 28.35 = 595.35 g

To convert from pounds (lb) to kilograms (kg), use the formula:

# of pounds x 0.454 =


For example, if you wanted to know how many kilograms were in 240 pounds, you would calculate it this way:

240 x 0.454 = 109 kg



To convert from short tons (T) to metric tons (t), use the formula:

# of short tons x 0.907 =


For example, if you wanted to know how many metric tons were in 10 short tons, you would calculate it this way:

10 x 0.907 = 9.07 t


NOTE: Metric tons can also be written as tonnes.

Some semi-trailer trucks weigh around 55 short tons.


Try This:


A semi-trailer truck weighs 55 short tons. How many metric tons is this? Some semi-trailer trucks weigh around 55 short tons.



55 x 0.907 = 49.89 t

The truck weighs 49.89 metric tons.



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