Grade 2
  1. Number Sense and Operations  1.1. Counting and Number Sequences  1.1.1. Counting up to 100  1.1.2. Counting by 2s, 5s, and 10s  1.1.3. Counting Backward from 20  1.1.4. Odd and even numbers in counting sequences  1.2. Place Value  1.2.1. Understanding ones and tens  1.2.2. Comparing Two-Digit Numbers  1.2.3. Identifying the Value of Each Digit in a Number  1.2.4. Building numbers using tens and ones  1.3. Addition and Subtraction  1.3.1. Basic addition up to 20  1.3.2. Basic subtraction up to 20  1.3.3. Addition with Regrouping  1.3.4. Subtraction with Borrowing  1.3.5. Solving word problems involving addition and subtraction  1.3.6. Addition and Subtraction with Multiples of 10  1.4. Odd and Even Numbers  1.4.1. Identifying Odd and Even Numbers  1.4.2. Understanding patterns in odd and even numbers  1.4.3. Simple operations with odd and even numbers
  2. Fractions and Decimals  2.1. Introduction to Fractions  2.1.1. Understanding halves and quarters  2.1.2. Representing fractions visually  2.1.3. Simple Fraction Comparisons  2.1.4. Writing Simple Fractions  2.1.5. Fractions as part of a whole  2.2. Fraction Equivalency  2.2.1. Understanding Equal Parts  2.2.2. Identifying Equivalent Fractions
  3. Measurement and Data  3.1. Length Measurement  3.1.1. Measuring objects using rulers  3.1.2. Comparing lengths  3.1.3. Estimating lengths  3.1.4. Understanding units of measurement (centimeters and inches)  3.1.5. Relating Length Measurements to Real-World Objects  3.2. Weight and Mass Measurement  3.2.1. Comparing Weights of Objects  3.2.2. Estimating weight in grams and kilograms  3.2.3. Using balance scales for comparison  3.3. Volume and Capacity Measurement  3.3.1. Understanding capacity with cups and liters  3.3.2. Comparing capacities of containers  3.3.3. Introduction to Milliliters  3.4. Time  3.4.1. Reading analog and digital clocks  3.4.2. Understanding hours and minutes  3.4.3. Calculating elapsed time in hours  3.4.4. Days of the week and months of the year  3.4.5. Understanding AM and PM  3.5. Money  3.5.1. Recognizing coins and bills  3.5.2. Counting money up to $1  3.5.3. Simple Addition and Subtraction with Money  3.5.4. Making Change for a Dollar
  4. Geometry and Spatial Reasoning  4.1. Shapes and Their Attributes  4.1.1. Identifying basic shapes (circle, triangle, square, rectangle)  4.1.2. Understanding sides and corners  4.1.3. Distinguishing between 2D and 3D shapes  4.1.4. Recognizing 3D Shapes (Cube, Sphere, Cone, Cylinder)  4.1.5. Composing and Decomposing Shapes  4.2. Symmetry  4.2.1. Understanding Lines of Symmetry  4.2.2. Drawing Symmetrical Shapes  4.2.3. Identifying Symmetrical Objects in the Environment  4.3. Patterns and Spatial Awareness  4.3.1. Recognizing and Creating Patterns  4.3.2. Extending Patterns  4.3.3. Understanding positions (left, right, above, below)  4.3.4. Using a grid to locate objects
  5. Data Handling and Probability  5.1. Collecting and Organizing Data  5.1.1. Using tally marks  5.1.2. Reading Bar Graphs  5.1.3. Simple Pictographs  5.1.4. Creating Bar Graphs from Given Data  5.2. Interpreting Data  5.2.1. Answering questions based on data  5.2.3. Identifying Most and Least in Data Sets  5.3. Introduction to Probability  5.3.1. Understanding likely and unlikely events

Grade 2 → Measurement and Data → Length Measurement ↓


Understanding units of measurement (centimeters and inches)


In grade 2 math, learning about length helps you understand how to measure the length or height of something. The two main units of measurement you will use often are centimeters (cm) and inches (in). Let's learn about these units and how to measure things using each.

What are centimeters and inches?

Centimeters and inches are units that help us measure length. Think of length as the distance from one end of something to the other.

Centimeter

A centimeter is a unit of measurement in the metric system. It is a small unit used to measure length and height. A centimeter is about as wide as a large paperclip or a little less than half an inch.

0 cm 1 cm

This line represents a distance of 1 centimetre.

Inch

An inch is a unit of measurement in the traditional system of units, often used in the United States. It is larger than a centimeter. An inch is approximately equal to the width of a large adult thumb.

0 inch 1 in

This line represents a distance of 1 inch.

Comparison of centimeters and inches

Let's compare centimeters and inches. Remember, an inch is longer than a centimeter. In fact, an inch is equal to about 2.54 centimeters. This means that if you measure something with both centimeters and inches, you will get a larger number in centimeters than in inches.

0 1 cm 2 cm 3 cm 1 in 2.54 cm

In the row above you can see that each segment marked for 1 inch is equal to 2.54 centimeters.

Learning to measure with a ruler

A ruler is a tool that helps you measure how long or big something is. Generally, rulers have both centimeter and inch markings.

When using a ruler:

  • Place the edge or beginning of the ruler at one edge of the object.
  • Then see where the other end of the object aligns with the numbers marked on the ruler.

Measuring in centimeters

When measuring in centimeters, you'll use the side of the ruler marked cm. The lines on this side are usually closer together than those on the inch side because centimeters are smaller units.

Measuring in inches

For inches, use the side marked with in. Numbers may increase by units or multiples, depending on the ruler.

Practical measurement example

Let's practice measuring some common objects. Don't forget to check whether you are using centimeters or inches depending on your ruler.

Example 1: Measuring a pencil

Take a pencil at home and measure it in both inches and centimeters.

Phase:

  • Line up one end of the pencil with the 0 mark on your ruler.
  • Read the number written on the other end. Record this number.

Your pencil might be about 15 cm long or about 6 in wide.

Example 2: Measuring a book

Try measuring the height or length of a book using a ruler.

Phase:

  • Place one edge of the book on the zero point of your ruler.
  • Check where the other edge falls on the ruler and write down this number.

The book may be about 25 cm or 10 in.

Fun activities

Here are some fun activities you can do to practice measuring in both centimeters and inches:

Scavenger hunt

With an adult's help, organize a hunt! Make a list of objects around the home/school that need to be measured. Measure each object in both centimeters and inches.

Measurement matching

Write down a few objects and ask your friend or family member to tell you the length of these objects in centimeters and inches. Then, measure to see which one is closest.

Why measuring is important

Measuring helps us with many daily tasks. Whether you're buying new furniture to fit your room, sewing clothes or just cooking according to a recipe, measurements help you be accurate and consistent.

Learning how to measure correctly using centimeters and inches will help you greatly both in school and in everyday life.

Summary

Let us summarize the main points about measuring length:

  • Length tells us how long or high something is.
  • Centimetre and inch are units of measuring length.
  • 1 inch is equal to 2.54 centimeters.
  • Use a ruler to measure objects, and always remember whether you are measuring in centimeters or inches.

By practicing measuring things around you, you will become more familiar with these units and be able to use the appropriate unit in different situations.

Dictionary

  • Centimeter (cm): A metric unit of length equal to one-hundredth of a meter.
  • Inch (in): A traditional unit of length based on the width of the thumb.
  • Ruler: An instrument used to measure length.

Grade 2 → 3.1.4


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Estimating lengths
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Understanding units of measurement (centimeters and inches)

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