LESSON Multiply decimal x decimal

4.6 Decimal Multiplication

Area = Length x Width

This is a pan of brownies. Four tenths is showing. I am going to take 0.2 of what is there. How much (of the original pan) am I going to take?

0.2 of 0.4 =

0.2 x 0.4 =

I will need to cut the pan horizontally into tenths.

I cut the pan horizontally into 10 equal rows (tenths).

Now I will shade in 2 of those rows across to represent two tenths (0.2).

The part that overlaps is the product...or how much of the original pan I am taking.

Count how many small squares there are OVERLAPPING and write your product as a decimal.

There are 8 small squares that overlap.

0.2 x 0.4 = 0.08

Multiple Choice

Which color represents the product for 0.3 x 0.4 = 0.12?

• red

• light blue

• purple

Multiple Choice

Which equation is represented?

• 0.3 x 0.7 = 0.21

• 0.7 x 0.7 = 0.49

Multiple Choice

This model shows the equation 0.3 x 0.4 = ?

(HINT: The purple part)

• 0.12

• 0.21

• 0.18

Multiple Choice

The equation modeled is

• 0.7 x 0.4

  Take four tenths of seven tenths

• 4 x 0.7

  four groups of seven tenths

Multiple Choice

The equation modeled is

• 0.3 x 0.5 = 0.15

• 3 x 0.5 1.5

Multiple Choice

• 9 x 0.2

• 0.9 x 0.2

Multiple Choice

• 0.2 x 0.9 = 0.18

• 2 x 0.9 = 0.18

Multiple Choice

• 0.5 x 0.4

• 0.6 x 0.4

Multiple Choice

• 0.6 x 0.6

• 0.9 x 0.6

Multiple Choice

• 0.1 x 0.2

• 1 x 0.02

Multiple Choice

• 0.1 x 0.5

• 0.5 x 0.5

Multiple Choice

• 3 x 0.7

• 0.3 x 0.7

Multiple Choice

• 3 x 9

• 0.3 x 0.9

Multiple Choice

• 0.2 x 0.8

• 2 x 0.8

Multiple Choice

• 0.1 x 0.2

• 2 x 0.1

0.3 of 0.9 = ?

• I started with 0.9 (yellow vertical columns).

• Then I shaded 0.3 (blue horizontal rows)

• The product is the part that overlaps in green.

• 27 small squares are green

• 0.3 x 0.9 = 0.27

​STILL CONFUSED?

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Multiple Choice

This model shows the equation 0.5 x 0.2 = ?

(HINT: The orange part)

• 0.10

• 0.80

• 0.60

Multiple Choice

What color represents the product of 0.7 x 0.2 = 0.14?

• yellow

  (7 rows across)

• dark green

  (2 columns up and down)

• light green

  (part that overlaps)

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​STILL CONFUSED?

​CLICK ON THE LINK FOR A VIDEO!