Rounding to the Nearest 10
13
10
7
0
234 + 788 =
1,022
Estimate the sum by rounding to the nearest 100:
354 + 271 =
700
Ms. Gianna has 3 shelves of books. Each shelf has 8 books. She gives 7 books to students. How many books does Ms. Gianna have now?
Write an equation with b to represent the unknown. Be sure to label your answer with a unit!
(3 x 8) - 7 = b
17 books
45
50
243
200
761 - 349 =
412
Estimate the difference by rounding to the nearest 100:
921 - 489 =
400
There are 16 boys and 12 girls in a classroom. Then 6 more students join the class. How many students are in the class now?
Write an equation with s to represent the unknown. Be sure to label your answer with a unit.
(16 + 12) + 6 = s
34 students
96
657
700
1,348 - 19 =
1,329
There are 209 students at the Harvard Kent. Over the summer, 121 more students enroll at the school. Mr. Ben estimates that there will be about 400 students enrolled at the Harvard Kent.
Does Mr. Ben's estimation make sense?
No, his estimation does not make sense. 209 rounds to 200. 121 round to 100. 100 + 200 = 300, not 400.
There are 8 boxes of crayons in Room 305. Each box has 6 crayons. 2 of the boxes have only pink crayons. Then, Ms. Marrero asks if she can borrow 5 crayons for art class. How many crayons are left over?
Write an equation with c to represent the unknown. Don't forget to label with a unit!
(6 x 8) - 5 = c
43 crayons were left over
235
240
987
1,000
Ms. Viola has 237 marshmallows. She gives 123 away to the students at the Harvard Kent. How many marshmallows does she have left?
Write an equation with m to represent the unknown. Make sure to label your answer with a unit.
273 - 123 = m
150 marshmallows
There are 598 kids at the water park. 220 of them go home because it is too hot. The life guard estimation that there are about 400 kids left at the park. Does his estimation make sense?
Yes, his estimation makes sense. 598 round to 600 and 220 rounds to 200. 600 - 200 = 400.
A school orders 9 boxes of notebooks. Each box has 12 notebooks. After some are given to students, 27 notebooks are left over. How many notebooks did the school give away?
Write an equation with n to represent the unknown. Be sure to label you answer with units!
(9 x 12) - n = 27
They gave away 81 notebooks.
895
900
732
700
Ms. Conran has 476 paperclips in her desk. Mr. Ben gives her 385 more. How many paperclips does she have in all?
Write an equation with p to represent the unknown. Make sure to label your answer with a unit.
476 + 385 = p
861 paperclips
At a concert, there are 589 audience members. During the concert it begins to rain and 109 people decide to leave. The manager estimates that there are about 800 people left at the venue. Does her estimation make sense?
No her estimation does not make sense. It does not make sense for there to be more people left at the venue than we started with because people left, not came. 589 rounds to 600 and 109 rounds to 100. 600 - 100 = 500. There would be about 500 people left, not 800.
A school buys 8 packs of pencils. Each pack has 9 pencils. They give away 17 pencils to students. Later, they buy 12 more pencils. How many pencils does the school have now?
Write an equation with p to represent the unknown. Be sure to label your answer with units!
(8 x 9) - 17 + 12 = p
67 pencils