Grade 4
  1. Numbers and Place Value  1.1. Understanding Place Value  1.2. Reading and Writing Large Numbers  1.3. Comparing and Ordering Numbers  1.4. Rounding Numbers  1.5. Understanding Odd and Even Numbers  1.6. Number Patterns and Sequences
  2. Addition and Subtraction  2.1. Addition of Large Numbers  2.2. Subtraction of Large Numbers  2.3. Estimation in Addition and Subtraction  2.4. Word Problems on Addition and Subtraction
  3. Multiplication and Division  3.1. Understanding Multiplication  3.2. Multiplying Multi-Digit Numbers  3.3. Understanding Division  3.4. Dividing Multi-Digit Numbers  3.5. Multiplication and Division Facts  3.6. Word Problems on Multiplication and Division
  4. Factors and Multiples  4.1. Understanding Factors  4.2. Finding Common Factors  4.3. Understanding Multiples  4.4. Finding Common Multiples  4.5. Prime and Composite Numbers  4.6. Prime Factorization  4.7. Greatest Common Factor  4.8. Least Common Multiple
  5. Fractions  5.1. Understanding Fractions  5.2. Equivalent Fractions  5.3. Simplifying Fractions  5.4. Comparing and Ordering Fractions  5.5. Addition of Fractions  5.6. Subtraction of Fractions  5.7. Mixed Numbers and Improper Fractions  5.8. Converting Mixed Numbers to Improper Fractions  5.9. Word Problems on Fractions
  6. Decimals  6.1. Understanding Decimals  6.2. Reading and Writing Decimals  6.3. Comparing and Ordering Decimals  6.4. Rounding Decimals  6.5. Addition of Decimals  6.6. Subtraction of Decimals  6.7. Converting Decimals to Fractions  6.8. Converting Fractions to Decimals  6.9. Word Problems on Decimals
  7. Measurement  7.1. Length  7.1.1. Units of Length  7.1.2. Converting Units of Length  7.1.3. Perimeter  7.1.4. Area  7.1.5. Word Problems on Length  7.2. Weight  7.2.1. Units of Weight  7.2.2. Converting Units of Weight  7.2.3. Word Problems on Weight  7.3. Volume and Capacity  7.3.1. Units of Volume  7.3.2. Converting Units of Volume  7.3.3. Estimating Volume and Capacity  7.3.4. Word Problems on Volume and Capacity  7.4. Time  7.4.1. Reading Time  7.4.2. Units of Time  7.4.3. Converting Units of Time  7.4.4. Calculating Elapsed Time  7.4.5. Word Problems on Time
  8. Geometry  8.1. Properties of Shapes  8.1.1. Types of Angles  8.1.2. Types of Triangles  8.1.4. Symmetry  8.1.5. Lines of Symmetry  8.2. Perimeter and Area  8.2.1. Perimeter of Rectangles  8.2.2. Perimeter of Other Shapes  8.2.3. Area of Rectangles  8.2.4. Area of Other Shapes  8.2.5. Area of Irregular Shapes  8.3. Coordinate Geometry  8.3.1. Understanding Coordinates  8.3.2. Plotting Points on a Grid  8.3.3. Identifying Shapes on a Grid
  9. Data and Graphs  9.1. Types of Data  9.2. Organizing Data  9.3. Reading Bar Graphs  9.4. Drawing Bar Graphs  9.5. Line Plots  9.7. Reading and Interpreting Line Graphs  9.8. Word Problems on Graphs
  10. Money  10.1. Understanding Money  10.2. Addition and Subtraction with Money  10.3. Making Change  10.4. Multiplying and Dividing Money  10.5. Word Problems on Money

Grade 4 → Decimals ↓


Subtraction of Decimals


Decimals are a way of representing numbers that are not whole. They are very useful in situations where you have to deal with fractions or parts of a whole. In this explanation, we will focus on how to subtract decimals. Learning to subtract decimals is important because it is a skill that is used in everyday situations, such as handling money or measuring objects.

Understanding decimals

Decimals have a whole number part and a fractional part that are separated by a decimal point. For example, in the decimal number 3.75, the number '3' is the whole number part, and '75' is the fractional part.

The positional value for decimals is as follows: the first place to the right of the decimal point is the tenth place, the second place is the hundredth place, and the third place is the thousandth place. For example, in the decimal number 4.926, '9' is in the tenth place, '2' is in the hundredth place, and '6' is in the thousandth place.

Basics of decimal subtraction

To subtract decimals, we follow the same steps as subtracting whole numbers. The most important thing is to line up the decimal points to make sure the corresponding place values are properly aligned. Let's walk through the steps.

Steps to subtract decimals

  1. Align the decimal points: Write the numbers one below the other so that their decimal points are in a straight line.
  2. Adjust for equal length: If the numbers do not have the same number of digits after the decimal point, make them equal in length by adding zeros to the end of the smaller number.
  3. Subtract as whole numbers: Starting with the rightmost digit, subtract each pair of digits just as you would with whole numbers.
  4. Borrow if necessary: If a digit in the upper number is smaller than the corresponding digit in the lower number, you must borrow from the next column to the left.
  5. Place the decimal point: Be sure to place the decimal point directly below the other decimal points in your answer.

Example 1

Subtract 5.32 from 8.56:

      8.56
    - 5.32
    ,
      3.24

phase:

  1. Align the decimal points: 8.56 is above 5.32.
  2. Subtract: Start with the rightmost digit:
    • 6 - 2 = 4
    • 5 - 3 = 2
    • 8 - 5 = 3

Understanding borrowing in decimal subtraction

Just like subtracting whole numbers, you may need to borrow when the digit of the top number is smaller than the corresponding digit of the bottom number. Let's consider an example where borrowing is necessary.

Example 2

Subtract 4.27 from 6.05:

      6.05
    - 4.27
    ,
      1.78

phase:

  1. Align the decimal points: 6.05 is above 4.27.
  2. Subtract: Start with the rightmost digit:
    • From the hundredths place: 5 is smaller than 7, so we borrow 1 from the tenths place. The tenths place becomes 9, and 5 becomes 15. Now 15 - 7 = 8.
    • From tenth place: 9 - 2 = 7.
    • From units place: 5 – 4 = 1 (after borrowing 1 decimal place from 6).

Why is subtracting decimals useful?

Learning how to subtract decimals is incredibly useful in everyday life. For example, when you're dealing with money, you'll often need to subtract amounts. Decimals can also be useful in measuring distance, weight, or any other measured quantity.

Imagine you are purchasing several items from a store and your budget is $20.00. You buy a shirt for $8.75 and a pair of socks for $3.45. To find out how much money you have left, you need to subtract these amounts from your budget.

Example 3

Subtract the total cost of the items from the budget:

      20.00
    - 8.75
    ,
      11.25

Then, subtract the cost of the next item:

      11.25
    - 3.45
    ,
       7.80

After buying the shirt and socks you will be left with $7.80.

Practice problems

It is important to practice subtracting decimals to gain confidence in solving such problems. Below are practice problems that will help you strengthen your skills.

  1. Subtract 7.49 from 15.90.
  2. Subtract 2.08 from 3.52.
  3. Subtract 19.82 from 25.55.
  4. Subtract 0.64 from 4.26.
  5. Subtract 5.77 from 12.30.

Solving these problems will give you a good understanding of subtracting decimals. Remember to align your decimal points, add zeros if necessary, and borrow when needed.

Common mistakes to avoid

Despite practice, it's easy to make mistakes when subtracting decimals. Here are some common mistakes to watch out for:

  • Not aligning the decimal points: This can result in numbers with the wrong place value.
  • Forgetting to add a zero: When numbers have different lengths after the decimal point, add a zero to make them easier to subtract.
  • Choosing the wrong answer: Make sure you choose the answer from the next leftmost digit, otherwise the answer may be marked wrong.

Recognizing these mistakes can improve accuracy when subtracting decimals.

Conclusion

Subtracting decimals is a valuable math skill and an essential part of understanding more complex math topics. From shopping to science, real-world applications often require the use of decimals, making it important to be able to subtract them accurately and efficiently.

Through visual examples, step-by-step processes, and common mistakes, hopefully this explanation has given you the understanding you need to perform decimal subtraction with confidence.


Grade 4 → 6.6


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Addition of Decimals
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Subtraction of Decimals

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