Grade 5, Module 1
Dear Parent/Guardian,
In Grade 5, Module 1 (Lessons 1.1 to 1.6), children build on their existing number
sense as they learn to read, write, picture, compare, and order large numbers (up
to hundreds of millions). Talk with your child about where he/she has seen or heard
very large numbers. Some examples might be population figures for various countries
around the world, budget or tax figures for state or federal governments, distances
in space, and so on. It can be fascinating to look up and compare some of these
figures. For example, what is the population of your town or city, as compared with
the population of your state, the entire USA, other large countries (like Canada or
India or China), or smaller countries (like Monaco or Luxembourg)? Talk with your
child about writing and comparing large numbers. Ask questions such as, “How would
you write out the number 290 million? Is that more or less than 520,000,000? Why?
If a small company makes a profit of $100,000 each year, how many years would it
take for the profit to total one million dollars? Fifty million dollars? Two hundred forty
million dollars?”
Exponential notation is often used to write very large or very small numbers (Lesson
5.2), for example, we can write 103 = 1,000 (which we read as “ten to the third power
equals one thousand”). The 10 is called the “base” and the 3 is called the “exponent.”
The exponent tells how many times you are multiplying the base times itself, so 103
means 10 × 10 × 10. Notice that when the base is 10 and the exponent is 1 or more,
the exponent is the same as the number of zeros at the end of the number, when
it is written out, so 108 = 100,000,000 (“10 to the 8th power equals 100 million). By
extension, we can write 5 × 107 = 50,000,000 or 230 × 104 = 2,300,000 (the fifth zero
comes from 230, because it is 23 × 10).
© ORIGO Education.
Sometimes when we’re dealing with very large numbers, we talk about them in terms
of fractions (of a million, etc.). For example, we can read 2,500,000 as “2 million
500 thousand” and we can also read/write it as “2 and a half million (or “2 1 million”
2
or “2.5 million”) since 500,000 is half of a million. Similarly, 1,250,000 is “one and
a quarter million” (or 1 1 million) and 30,750,000 is “30 and three quarter million”
4
(or 30¾ million). Talking about large numbers this way helps with estimation and
communication. For example, if we read that the population of Idaho is 1,595,728 we
can say that it is “a little more than 1 and a half million” or “a little more than 1.5 million.”
Multiplication strategies are the second major topic in Module 1. In Lesson 1.8, children
explore multiplication patterns to see how problems involving small numbers can
reveal answers to problems involving much larger numbers. For example, if we know
3 × 4 = 12, then we can easily see why 3 × 40 = 120 and 3 × 400 = 1200. Lessons
1.9 to 1.12 review, extend, and compare strategies for multiplying mentally that were
introduced in Grade 4.
Your Grade 5 Teacher
Common Core Focus
Numbers in the millions
(representing, reading,
writing, comparing,
and ordering large
numbers); multiplication
strategies (using
multiplication patterns,
doubling and halving,
using the distributive
property, mental
computation).