Multiplying, Dividing, and Estimating with Scientific Notation

Multiplying, Dividing,
and Estimating with
Scientific Notation

Lesson 14

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Let’s multiply and divide
with scientific notation to
answer questions about
animals, careers, and
planets!

Biomass

● MLR5: Co-Craft Questions and Problems

Comprehend/Apply: Activity 14.2

How many humans
do you think there
are for each cat in
the world?

Large numbers like populations are often
estimated using scientific notation.

In the world there are an estimated
7.5 ✕ 10⁹ humans and 7.5 ✕ 10⁹ cats!

So there are roughly 12.5 humans for each cat.

Use the table to answer
questions about different
creatures on the planet.

Be prepared to explain your reasoning.

★

Estimation will help
answer these questions
much more easily!

Work as a team to
complete the task.

Which creature is the least
massive?

Estimate how many times
more ants there are.

1

Which creature is the least
massive?

Estimate how many times
more massive a human is.

2

Which is more massive, the
total mass of all the
humans or the total mass
of all the ants?

About how many times
more massive is it?

3

Which is more massive, the
total mass of all the krill or
the total mass of all the
blue whales?

About how many times
more massive is it?

4

How did you use scientific notation
and estimation to compare
quantities?

Organize: Activity 14.2 Synthesis

Distances in the
Solar System
●

MLR7: Compare and Connect

●

Notice and Wonder

Comprehend/Apply: Activity 14.3

What do you notice?

What do you wonder?

Begin working on
the task as a team.

Check in and compare
your estimations as you
work. Work together to
reach an agreement.

Estimate how many
Earths side-by-side
would have the same
width as the sun.

1

Estimate how many
Earths it would take to
equal the mass of the
Sun.

2

Estimate how many
times as far away from
Earth the planet
Neptune is compared
to Venus.

3

Estimate how many
Mercuries it would take
to equal the mass of
Neptune.

4

How was scientific notation useful
in answering these questions?

Organize: Activity 14.3 Synthesis

What did you notice
about the numbers in the
tables you saw today?
They were all written in
scientific notation.

Organize: Lesson 14 Synthesis

A number is expressed in scientific
notation if it is the product of an integer
power of 10 and a number greater than or
equal to 1 but less than 10.

How does the convention about the
numeric factor help us quickly get an
idea about the size of a number?

How does it help us compare numbers?

Two Additional Practice Problems

Multiple Choice

The Click-O Pen Company produced $$1.8\times10^6$$ each year for 4 years. What was the total number of pencils the Click-O Pen Company produced during those 4 years?

• $$7.2\times10^6$$

• $$7.2\times10^{10}$$

• $$7.2\times10^{24}$$

• $$7.2\times10^{30}$$

Multiple Choice

A light year is defined as the distance light travels in one year. One light year is 9.46 × 10¹² kilometers. A galaxy is about 150,000 light years wide. About how many kilometers wide is the galaxy?

• $$1.419\times10^{16}$$

• $$1.419\times10^{17}$$

• $$1.419\times10^{18}$$

• $$1.419\times10^{19}$$

Today’s
Goals

❏ I can multiply and divide

numbers given in
scientific notation.

❏ I can use scientific

notation and estimation
to compare very large or
very small numbers.

Estimating with
Scientific Notation

Summarize/Apply: Cool Down 14.5