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Rounding
Find The Value of Each Sum
Find The Difference
Write The Equation!
Does This Make Sense?
100

Round 115 to the nearest ten

What is 120?

100

225+122=

What is 347?

100

What operation do you do when you are asked to find the difference?

What is subtraction?

100
There are 52 apples in a basket. 3 students each take 5 apples from the basket. The number of apples left in the basket is b. Which equation represents the situation?

a. 52-5=b                  c. b-(3x5)=52

b. 52+(3x5)=b.          d. b=52-(3x5)

b=52-(3x5)

100

A question in a subtraction situation can be answered with an estimate of “about 200.” What could the subtraction situation be?

150-249

200

Round 350 to the nearest hundred.

What is 400?

200

489+156=

What is 645?

200

556-126=

What is 430?

200

There are 145 balloons at the party. 45 of the balloons flew away and got stuck in a tree. Some balloons got stuck in a tree. There were 82 balloons left at the party. How many balloons got stuck in the tree?

a. 145-45-b=82           c. 45-b+145=82

b. 145+45-b=82          d. 45-b=145

What is 145-45-b=82?

200

What are all the numbers that round to 350 when rounded to the nearest 10?

345-354

300

What is 238 to the nearest 100 and to the nearest 10?

What is 200 and 240
300

Write 856 in expanded form

800+50+6

300

512-345=

What is 167?

300

There are 345 seats in the auditorium. 125 students from Hadley School sat in the seats. 97 students from Clarke School sat in the rest of the seats. How many seats are left?

What is 123 seats?

300

There are seats for 80 students on the bus. There are 24 students from Mrs. Rosenthal's class on the bus and 28 students from Mrs. G's and Mrs. Vockley's class. Do you think there will be more or less than 50 empty spots of the bus?

Less

400

Round 952 to the nearest 100.

What is 1,000?

400

621+264=

What is 885?

400

Find the value of 879-239.

What is 640?

400

Andre has 245 cards. He bought 7 more packages of cards. How many cards does he have now?

What information do you need to know to be able to answer the question?

What is how many cards are in each package?

400

There are seats for 400 students. There are 123 students from Jen's school and 156 students from Ben's school. 

Jen estimates that there will be about 200 empty seats. Do you agree with Jen?

Disagree because 123 rounds to 120 and 156 rounds to 160. 160+120=280 students in seats.



500

Round 205 to the nearest ten.

What is 210.
500

Use expanded form to add 546+239.

500+40+6 

200+30+9

700+70+15=785

500

540-345=

What is 195?

500

Santa's elves are packing 128 presents for Santa to deliver to the good boys and girls. The elves pack 5 bags of gifts with 10 presents in each bag. How many presents are left to pack?

128-(5x10)=

128-50=78 presents left to pack

500

About how many empty seats will there be?

There will be about 400-280=120 empty seats