How to Set Up Your Do Now Notebook
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!
Do Now # 1 – Thurs, 9/121) 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
Chapter 1 Lesson 1 Estimating with Whole Numbers
Why Estimate???
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.
How do we Estimate???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…
How do we figure out which numbers are COMPATIBLE ?
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.
How do we ROUND???
4 or below, leave it alone…5 or above, give it a shove…
Steps1) Underline the digit in the indicated place
value position2) 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.
Let’s review place value positions
Round to the thousands place value
Let’s Practice Rounding
941,312
tensTen thousandshundredsHundred thousands
Number Compatible Number
Let’s Practice Compatible Numbers (not given a place value to round to)
48953
2,71354198,312
Remember use Rounding RulesWhen 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.
Remember!
4 or below leave it alone…5 or above give it a shove…
Example 1 Estimate the sum by rounding to the place value indicated. 12,345 + 62,167; ten thousands
Where do we start??1) Identify the digit in the indicated place value position2) Look at the number to the RIGHT
3) Round
REMEMBER… 4 or below, leave it alone 5 or above, give it a shove
4) Change ALL numbers to the right to Zeros.5) Add
Example 1…worked out
Example 2Estimate the sum by rounding to the place value indicated. 4,983 – 2,447; thousands
Example 3Estimate the sum by rounding to the place value indicated. 4,983 – 2,447; hundreds
You Try…Estimate the sum by rounding to the place value indicated. 43, 312 + 131, 653; thousands
Over??? Under???
An estimate that is less than the exact answer is an underestimate.
An estimate that is greater than the exact answer is an overestimate.
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.
Word Problem 1
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 8 20 = 160 players
How we find EXACT
answer
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?
Word Problem 2
What operation do we need to solve this?
Can we find compatible numbers for each?
Ms. Oliver wants to buy the entire seventh-grade new pencils. There are 5 seventh-grade homeroom classes of 28 students. Estimate how many pencils Ms. Oliver needs to buy for all of the students.
You Try…Word Problem
Text pg 4#1-12
Independent Practice
