➗ Rounding Decimals

📖 What the Section Is About

In this section, students learn how to round decimals to the nearest whole number, tenth, or hundredth. They use place value and the rounding rule to decide whether to keep a digit the same or increase it by one. Students apply rounding in real-life situations like estimating money, measurements, and distances.

🎯 Learning Objectives

✅ Identify place value positions in decimals (ones, tenths, hundredths)
✅ Round decimals to the nearest whole number
✅ Round decimals to the nearest tenth or hundredth
✅ Apply the 5-or-more-round-up rule correctly
✅ Use rounding to estimate in real-world contexts

🧮 Examples

Example 1: Rounding to the Nearest Whole Number
• 3.6 → 4 because the tenths digit (6) is 5 or more

Example 2: Rounding to the Nearest Tenth
• 4.38 → 4.4 because the hundredths digit (8) is 5 or more

Example 3: Rounding to the Nearest Hundredth
• 2.476 → 2.48 because the thousandths digit (6) is 5 or more

Example 4: Real-World Context
• $5.76 rounded to the nearest dollar = $6

🔢 Understanding How to Round

1️⃣ Find the Target Place – Whole number, tenth, or hundredth
2️⃣ Look at the Next Digit – Check the digit to the right of the target place
3️⃣ Apply the Rule – If the digit is 5 or more, round up; if less than 5, keep it the same
4️⃣ Replace Lower Digits with Zeros (for whole numbers) or Drop Them (for decimals)

📘 Key Vocabulary and Definitions

• Decimal – A number showing parts of a whole using place value
• Tenth – One of ten equal parts (0.1)
• Hundredth – One of one hundred equal parts (0.01)
• Round – To make a number simpler while keeping its value close
• Estimate – An approximate value close to the exact amount

🎲 Fun Practice Activities

🎲 Decimal Dice – Roll two dice to make a decimal, then round to different places
🎲 Price Rounding Game – Round prices to the nearest dollar or ten cents
🎲 Rounding Relay – Teams race to round decimal numbers correctly

🏡 Offline Homework Idea: “Bill Estimate”

Look at a shopping receipt. Round each price to the nearest dollar and find the estimated total.