Decimal Concept

Decimal numbers

UNIT 4.

A decimal number has an integer part and a decimal part, separated by a comma.

In Spanish, we use a comma (,). However, in English, we use a decimal point (.).

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UNIT 4.

​Definition.

Twelve point three

Zero point twenty-one

One point zero five

12.3

0.21

1.05

How to read decimal numbers.

UNIT 4

Quiz

Which number are we talking about?

Fill in the Blanks

Twelve point three

Fill in the Blanks

Fifty point zero three

Fill in the Blanks

ten point fifty-two

Fill in the Blanks

Two hundred point three

< ... is less than ...

> ... is greather than ...

= ... is equal to...

​Remember

1.23 < 1.3

2.3 > 2.03

3.4 = 3.40

We can order decimal numbers

UNIT 4.

Quiz

How can we order the following decimal numbers?

Multiple Choice

Which one is correct?

• 31.23 < 31.24

• 31.23 > 31.24

Multiple Choice

Which one is correct?

• 31.23 < 31.2

• 31.23 > 31.2

Multiple Choice

Which one is correct?

• 31.23 < 31.02

• 31.23 > 31.02

Multiple Choice

Which one is correct?

• 31.23 < 31.3

• 31.23 > 31.3

Multiple Choice

Which one is correct?

• 31.2 < 31.3

• 31.2 > 31.3

Multiple Choice

Which one is correct?

• 31.2 < 31

• 31.2 > 31

We should align the numbers on the commas (or decimal points) and add or subtract just like with integers.

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UNIT4.

​Addition and subtraction

Quiz

Do these calculations.

Fill in the Blanks

3.06 + 2.52 =

Fill in the Blanks

3.06 - 2.52 =

Fill in the Blanks

21.2 + 3.41 =

Fill in the Blanks

21.2 - 3.41 =

You should multiplicate without commas and count the total number of digits on the right side of the commas in the two numbers multiplied. The final result will have this many digits to the right of the comma.

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UNIT 4.

​Multiplication

Quiz

Do these calculations.

Multiple Choice

$$2.3\ ·\ 1.2\ =$$

• 2.76

• 27.6

• 0.276

• 276

Multiple Choice

$$2.3\ ·\ 0.5\ =$$

• 1.15

• 11.5

• 0.115

• 115

Fill in the Blanks

$32.5\ ·\ 2.5\ =$

Fill in the Blanks

$0.5\ \cdot\ 0.3\ =$