Topics
9. Measurement
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United States of AmericaUT
Grade 3

9.02 Measure and estimate mass

Lesson
Practice
Lesson

Are you ready?

Do you remember the units of mass? Let's try these problems to practice.

It is most appropriate to use grams to measure:

  1. Your mass

    A

    Your pencil case

    B

    A bus

    C

It is most appropriate to use kilograms to measure:

  1. An eraser

    A

    A button

    B

    A bike

    C

Learn

When measuring the mass of an object, we have two main methods.

  1. We can balance a scale with weights that we already know. 
  2. We can measure the mass by reading a mechanical scale.

This video looks at measuring the mass of objects using a scale. 

It is useful to know the mass of some common objects so that we can estimate the mass of new objects.

Apply

Question 1

The scale below shows an object balanced evenly with a particular set of weights.

  1. The following weights were on the scale:

    What is the total mass of the object?

Question 2

What measurement is indicated on this scale?

QUESTION 3

Choose the best estimate for the mass of a school student.

  1. $40$40 g

    A

    $400$400 g

    B

    $4$4 kg

    C

    $40$40 kg

    D

Remember!

A gram has a mass similar to a piece of paper, or a feather. A kilogram has a mass similar to a $1$1 liter bottle of milk or juice. We can measure the mass of objects with different types of scales. Mechanical scales are just like a number line, but in a circle.

Outcomes

3.MD.2

Measure and estimate liquid volumes and masses of objects using standard units of grams (g), kilograms (kg), mililiters(ml), and liters (l). Excludes compound units such as cubic centimeters [cc or cm3] and finding the geometric volume of a container.) Add, subtract, multiply, or divide to solve one-step word problems involving masses of objects or volumes of liquids that are given in the same units, for example, by using drawings (such as a beaker with a measurement scale) to represent the problem. (Excludes multiplicative comparison problems.)

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