Lesson 1.5

Comparing and Ordering Decimals

Comparisons! ipad vs. windows tablet

The Science teachers decided it would be fun to measure some ants…

1. The first ant measured 0.521 centimeters.

2. The second ant measured 0.498 centimeters.

3. The last ant measured 0.550 centimeters.

Which ant was longest?Which was shortest?

Let’s compare these numbers by looking at the values of each digit starting with the tenths place.

0.4980.5210.550

Are the tenths digits the same or different?

So, which ant is smallest?

Now compare the hundredths digits.

Which ant is the next smallest?

Let’s write it! We call these comparisons INEQUALITIES,

since the numbers AREN’T equal! We use the < “less than,” and > “greater

than” symbols to show the relationship between the numbers.

When we write two or more numbers down and compare them using symbols, we call it a “number sentence.”

0.498 < 0.521, and 0.521 < 0.550 0.550 < 0.521, and 0.521 < 0.498

These are number sentences.

To Review…1. Line up the decimal points of the

numbers you are comparing. 2. Start at the left. 3. Compare digits of the same place

value. 4. Move one place to the right. 5. Compare digits of the same place

value. 6. Repeat until there are no more digits. 7. Record the digits in correct order.

Time to practice!

• Follow your teacher’s directions to get in small groups/partners.

• Each person write down a decimal. It must be four digits, and greater than 1, but less than 2.

• Share your number with your partner, and compare them to find which is larger.

• Write two number sentences that compare your numbers.