Lesson 1.13: Decimals – Place Value, Comparing, Ordering & Rounding | SEA Mathematics | My Carib Academy
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🔢 Lesson 1.13: Decimals – Place Value, Comparing, Ordering & Rounding

Master decimal notation, place value to hundredths, comparing, ordering and rounding decimals. This lesson covers SEA Mathematics Objectives 71-81 from the Number Strand.

65 Minutes
Module 1: Number
Objectives 71-81
4 Videos
Lesson Progress 0%

Previous Lesson

Did you complete Lesson 1.12? Review Fraction Word Problems →

Learning Objectives

By the end of this lesson, you will be able to:

  • Read and write decimals to hundredths in numerals and words (Objectives 71-74)
  • State the place and value of digits in decimals to hundredths (Objectives 75-76)
  • Compare and order decimals to hundredths (Objectives 77-79)
  • Round decimals to the nearest whole number or tenth (Objectives 80-81)

SEA Tip

Decimal questions appear in Section I, II, and III of the SEA Math paper. These are essential for money and measurement! (SEA Framework Page 21-22)

Watch: Decimal Place Value

Start by watching this video to learn about decimal place value to hundredths. Take notes as you watch! 📝

Decimal Place Value – Mathematics Video Lesson

Quick Check

Did you understand the video? Review the notes below before continuing! ✅

Decimal Notation & Place Value

Decimals are another way to write fractions. The decimal point separates the whole number from the fractional part.

Understanding Decimals

  • Ones: Whole numbers to the LEFT of the decimal point
  • Tenths: First digit to the RIGHT of the decimal point (1/10)
  • Hundredths: Second digit to the RIGHT of the decimal point (1/100)

📊 Decimal Place Value Chart:

Ones Decimal Point Tenths Hundredths
3 . 4 7
3 ones decimal point 4 tenths (0.4) 7 hundredths (0.07)

Read as: Three and forty-seven hundredths

📊 Example 1: Writing Decimals in Words

Convert to Words

Problem: Write 5.23 in words

Solution:

  1. Whole number: 5 = five
  2. Decimal part: 23 = twenty-three hundredths
  3. Combine: Five and twenty-three hundredths

Answer: Five and twenty-three hundredths

Common Mistake

Always say “and” for the decimal point when reading decimals in words!

Watch: Comparing Decimals

Now watch this video to learn how to compare decimals. Pay attention to place value! 🎯

Comparing Decimals – Mathematics Video Lesson

Comparing Decimals

To compare decimals, start from the LEFT and compare each place value.

📋 Steps for Comparing Decimals:

Step-by-Step Method
  1. Compare the whole numbers (ones) first
  2. If equal, compare the tenths
  3. If still equal, compare the hundredths
  4. Use symbols: > (greater than), < (less than), = (equal to)

📊 Example 2: Comparing Decimals

Which is larger: 3.45 or 3.54?

Solution:

  1. Compare ones: Both have 3 → Equal
  2. Compare tenths: 4 vs 5 → 5 is larger
  3. Answer: 3.54 > 3.45

Answer: 3.54 is larger

Watch: Rounding Decimals

Watch this video to learn how to round decimals to the nearest whole number or tenth. 🎯

Rounding Decimals – Mathematics Video Lesson

Rounding Decimals

Rounding decimals is similar to rounding whole numbers. Look at the digit to the RIGHT of the place you’re rounding to.

📋 Rounding Rules:

Step-by-Step Method
  1. Identify the place you’re rounding to
  2. Look at the digit to the RIGHT
  3. If 0-4: Round DOWN (keep the digit the same)
  4. If 5-9: Round UP (add 1 to the digit)
  5. Drop all digits to the right

📊 Example 3: Rounding to Nearest Whole Number

Round 4.73 to the nearest whole number

Solution:

  1. Identify: Ones place = 4
  2. Look right: Tenths = 7
  3. 7 is 5-9: Round UP
  4. Answer: 5

Answer: 5

📊 Example 4: Rounding to Nearest Tenth

Round 3.42 to the nearest tenth

Solution:

  1. Identify: Tenths place = 4
  2. Look right: Hundredths = 2
  3. 2 is 0-4: Round DOWN
  4. Answer: 3.4

Answer: 3.4

Watch: Ordering Decimals

Watch this video to learn how to order decimals from least to greatest or greatest to least. 📊

Ordering Decimals – Mathematics Video Lesson

Ordering Decimals

Ordering decimals uses the same skills as comparing. Line them up by place value!

📊 Example 5: Ordering Decimals

Order from least to greatest: 2.3, 2.03, 2.33

Solution:

  1. Line up by decimal point:
  2. 2.30 (add zero to make same places)
  3. 2.03
  4. 2.33
  5. Compare: 2.03 < 2.30 < 2.33

Answer: 2.03, 2.3, 2.33

Quick Tip

Add zeros to make all decimals have the SAME number of decimal places. This makes comparing easier!

Quick Quiz

Test your understanding! Select an answer for each question. 🔢

6 Questions
12 Minutes
70% to Pass

1. What is the value of 5 in 3.57?

2. Which is larger: 4.56 or 4.65?

3. Round 7.82 to the nearest whole number

4. Write 2.35 in words

5. Order from least to greatest: 1.2, 1.02, 1.22

6. Round 5.67 to the nearest tenth

0/6

Lesson Complete!

Great job finishing Lesson 1.13! You’re mastering decimals for the SEA exam! 🎉

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