Date
Do Now # _______
IMPORTANT NOTE!
•Every Do Now entry must have the heading of the date and the do
now number.
•Draw a line at the end of each Do Now entry. You will write the next
day’s Do Now underneath it.
•DO NOT use a new page for each Do Now entry!
•Use the back of notebook pages too!
•If you do not follow these instructions and run out of paper, you must
buy your own Do Now notebook!
1) 500 – 324
2) 38,000 – 5,356
3) Explain how you regrouped to subtract in
the above problems.
Chapter 1
PreTest
Dipstick Quiz & Materials
Collection
Estimating with Whole Numbers
Sometimes in math you do not need an
exact answer. Instead, you can use an
estimate.
Estimates are close to the exact answer
but are usually easier and faster to find.
When estimating, you can round the
numbers in the problem to compatible
numbers.
Compatible numbers are close to the
numbers in the problem, and they can help
you do math mentally.
To find a compatible number when
estimating you must ROUND to an
indicated place value position…
Remember this saying…
4 or below, leave it alone…
5 or above, give it a shove…
You use this phrase when rounding, by looking
ONLY at the number to the RIGHT of the
indicated place value position.
After you have decided to round up or down, you
MUST change ALL the numbers to the right of
the indicated place value position to ZEROS.
Steps
1) Underline the digit in the indicated place
value position
2) Circle the number to the right of it
3) If the circled number to the right of the
indicated place value position is…
4 or below leave the underlined digit alone
5 or above ROUND UP the underlined digit
4) Change all numbers to right of the place
value position to zeros.
thousands place value
Round to the Hundred
thousands
Ten
thousands
hundreds
tens
941,312
Number
98,312
2,713
541
953
48
Compatible Number
Remember!
When rounding, look at the digit to the
right of the place to which you are
rounding.
• If that digit is 5 or greater, round up.
• If that digit is less than 5, leave the
number alone.
4 or below leave it alone…
5 or above give it a shove…
Estimate the sum by rounding to the place value
indicated.
12,345 + 62,167; ten thousands
1)
3)
Round
in the
indicated
2)
Look
the
number
toto
the RIGHT
4)
Change
ALLdigit
numbers
5)Identify
Add atthe
place
value
the right
toposition
Zeros.
REMEMBER…
4 or below, leave it alone
5 or above, give it a shove
Where do we start??
Estimate the sum by rounding to the place value
indicated.
4,983 – 2,447; thousands
Estimate the sum by rounding to the place value
indicated.
4,983 – 2,447; hundreds
Estimate the sum by rounding to the place value
indicated.
43, 312 + 131, 653; thousands
An estimate that is greater than the
exact answer is an overestimate.
An estimate that is less than the exact
answer is an underestimate.
Chelsea is planning the annual softball
banquet for the 8 teams in the region.
Each team has 18 members. Estimate
how many plates she will need to buy
if all the members attend.
How would we solve
this if it wasn’t an
estimation problem?
Chelsea is planning the annual softball
banquet for the 8 teams in the region. Each
team has 18 members. Estimate how many
plates she will need to buy if all the
members attend.
Find the number of softball members.
8  18
How we find
EXACT
answer
8  20 = 160 players
ESTIMATE: the
number of
players in each
team
Chelsea would need about 160 plates.
Is this an overestimate or underestimate?
Mrs. Blair will drive 103 miles to the
airport at 55 mi/h. About how long
will her trip take?
What operation do we need to
solve this?
Can we find compatible numbers
for each?
Ms. Oliver wants to buy the entire seventhgrade new pencils. There are 5 seventhgrade homeroom classes of 28 students.
Estimate how many pencils Ms. Oliver
needs to buy for all of the students.
Text pg 4
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