Place Value with Decimals (Thousandths) • Topic 2 of 3

Rounding Decimals

What is Rounding?

Rounding makes numbers easier to work with by finding the closest "nice" number.

Steps to Round Decimals:

Find the place value you're rounding to (tenths, hundredths)
Look at the digit to the right
If it's 5 or more → round UP
If it's 4 or less → round DOWN (stay same)

Rounding to Tenths:

3.47 → Look at hundredths place (7 ≥ 5) → round up → 3.5
3.42 → Look at hundredths place (2 ≤ 4) → round down → 3.4

Rounding to Hundredths:

5.673 → Look at thousandths place (3 ≤ 4) → round down → 5.67
5.678 → Look at thousandths place (8 ≥ 5) → round up → 5.68

ROUNDING NUMBER LINE (to nearest tenth):

    3.40    3.45    3.50
      │       │       │
      ▼       ▼       ▼
      ├───────┼───────┤
      │       │       │
      
    3.42 → closer to 3.40 → rounds to 3.4
    3.47 → closer to 3.50 → rounds to 3.5
    
ROUNDING DECISION TREE:

    Start: Find rounding place
              │
              ▼
    Look at digit to the right
              │
        ┌─────┴─────┐
        ▼           ▼
    Is it ≥ 5?   Is it ≤ 4?
        │           │
        ▼           ▼
    Round UP    Round DOWN
    (add 1)     (stay same)

Solved Examples

Worked Example

Round 7.348 to nearest tenth

Solution

Tenths place: 3 (7.3__)
Look at hundredths: 4
4 ≤ 4 → round down
Answer: 7.3

Worked Example

Round 12.567 to nearest hundredth

Solution

Hundredths place: 6 (12.56_)
Look at thousandths: 7
7 ≥ 5 → round up (6 becomes 7)
Answer: 12.57

Worked Example

Round 0.999 to nearest tenth

Solution

Tenths place: 9 (0.9__)
Look at hundredths: 9
9 ≥ 5 → round up (9 becomes 10, carry over)
0.9 + 0.1 = 1.0
Answer: 1.0

Key Points

5 or more? Round up! (5,6,7,8,9)
4 or less? Round down! (0,1,2,3,4)
Rounding to tenths → look at hundredths
Rounding to hundredths → look at thousandths
Rounding can cause carries (0.999 → 1.0)

Quick Check — 4 MCQs

Tap an option to check your answer0 / 4

Q1.To round, look at the digit to the ___ of the rounding place.

Explanation: The digit to the right.

Q2.If that digit is $5$ or more, you:

Explanation: Round up.

Q3.$0.47$ rounded to the nearest tenth is:

Explanation: $0.5$.

Q4.$0.83$ rounded to the nearest tenth is:

Explanation: $0.8$.

Practice more MCQs → 📝 Assignment · 35 marks