2.2.5 Decimals in Daily Life

Think about when and how often you encounter decimals on a daily basis. You might meet decimals in your everyday life when you are shopping, such as prices or discounts, or measuring something, such as how tall you are or how far it is from your home to college. Try to think of a few and ask your friends what they use decimals for or where they have seen them.

Activity symbolActivity: Sunflowers and Winners

In a sunflower competition, Ahmed, Bert, and Cathy had the three tallest sunflowers. The heights of the sunflowers were measured; Ahmed’s is 1.8 feet tall, Bert’s is 1.67 feet tall, and Cathy’s is 1.72 feet tall. Which is the tallest sunflower? Which of these is the shortest?

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Discussion

Create a table that breaks down each height into its placeholders.

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Answer

To decide which of these three numbers is largest, you can either draw a number line and mark the heights on it, or use a place value table as shown below.

UnitsTenthsHundredths
Ahmed180
Bert167
Cathy122

Starting at the left-hand column, compare the digits in each column.

All the digits in the units column are 1, so you need to look at the tenths column. The first number has eight tenths, the second number has six tenths and the final number has seven tenths.

  • First place: Ahmed with the biggest sunflower at 1.8 feet.
  • Second place: Kathy with the second biggest sunflower at 1.72 feet.
  • Third place: Bert with the third biggest sunflower at 1.67 feet.

2.2.4 More Practice with the Number Line