Number Line and Rounding
Where would you place 42 on a number line? (Name the consecutive multiples of 10 it is between.)
Between 40 and 50
What is 125 + 250? (Show with a number line.)
375
What is the value of three quarters?
(Draw a strip diagram to represent.)
75 cents
Estimate the sum of 43 + 29 by rounding to the nearest ten. (Explain using a number line.)
About 70
What is a strip diagram? (Define it using vocabulary.)
A visual representation of parts and the whole, often used to show addition or subtraction.
Round 87 to the nearest 10.
90
Solve: 800 - 425. Use a strip diagram to show your thinking.
375
If you have $5 in coins consisting of two $1 bills and three $1 coins, what is the total? (Use a number line to represent.)
$5
Estimate the difference of 78 - 34 by rounding. (Represent on a number line.)
About 40
Use a part-part-whole model to represent: 12 + 8.
Whole: 20; Part 1: 12; Part 2: 8.
Show where 156 would go on a number line and describe its position relative to 100 and 200.
It is closer to 100 than 200.
If you have 340 apples and give away 125, how many do you have left? (Represent using a part-part-whole model.)
215 (340 is the whole; 125 is part 1, 215 is part 2.)
Determine the total value of: 2 dimes, 3 nickels, and 4 pennies. (Use a strip diagram to show the parts.)
34 cents
Use compatible numbers to estimate the sum of 56 + 23. (Show with a strip diagram.)
80
Show how to solve 70 - 25 using a number line.
Start at 70 and move left 25.
Use a number line to estimate the sum of 38 + 24. Where would you mark the result?
About 62 on the number line.
Represent the problem: Sarah has 250 marbles and buys 150 more. Show with a strip diagram.
250 + 150 = 400
Round 245 and 376 to the nearest hundred and estimate their sum using a number line.
200 + 400 = 600
Create a strip diagram for the problem: 50 is the whole, and one part is 20. What is the other part?
30 (50 - 20 = 30)