Compatible numbers are the numbers that are easy to add, subtract, multiply, or divide mentally (in your head).
Rounded numbers are an integer that ends with one or more "0"s.
Which box below represents compatible numbers and which box below represents rounded numbers?
Turn & Talk (level 1)
Which method of estimation do you think is easier, compatible numbers or rounded numbers? Why?
Sentence Stem:
I think the easier method of estimation is to use _______________ because __________________________.
Vocabulary
compatible numbers approximate round
rounded numbers estimate add/ subtract
Use a complete sentence to answer the following question.
Which method of estimation do you think is easier, compatible numbers or rounded numbers? Why?
57 rounded to the nearest 10 is
91 rounded to the nearest 10 is
42 rounded to the nearest 10 is
25 rounded to the nearest 10 is
Round to the nearest ten.
Example: 237 → _240_
132 →
743 →
336 →
Round to the nearest hundred.
Example: 2,432 → _2,400
4,768 →
2,423 →
8,462 →
Round to the nearest ten.
Example: 2,453 → __2,450__
3,682 →
54,637 →
41,608 →
Round to the nearest hundred.
Example: 47,286 → __47,300__
25,473 →
53,729 →
67,821 →
Round to the underlined number.
Example: 472,563 → _473,000_
854,368 →
91,483 →
748,924 →
Round to the leading digit.
Example: 472,563 → _500,000_
8,328 →
683 →
748,924 →
Estimate the sum or difference by rounding to the nearest ten.
Example:
28 + 17 → __30__ + __20__ = __50__
17 + 23 → + =
Estimate the sum or difference by rounding to the nearest ten.
Example:
28 + 17 → __30__ + __20__ = __50__
42 + 37 → + =
Estimate the sum or difference by rounding to the nearest ten.
Example:
28 + 17 → __30__ + __20__ = __50__
38 − 14 → − =
Estimate the sum or difference by rounding to the nearest ten.
Example:
28 + 17 → __30__ + __20__ = __50__
9 + 63 → + =
Estimate the sum or difference by rounding to the nearest ten.
Example:
28 + 17 → __30__ + __20__ = __50__
68 − 21 → − =
Estimate the sum or difference by rounding to the nearest ten.
Example:
28 + 17 → __30__ + __20__ = __50__
12 + 82 → + =
Round to the nearest ten.
Example: 263 → _260_
164 →
Round to the nearest hundreds.
Example: 6,473 → _6,500_
7,564 →
Round to the underlined digit.
Example: 34,562 → _34,600_
34,269 →
Round to the leading digit.
Example: 49,502 → _50,000_
723,483 →
Estimate the sum or difference by rounding to the nearest ten.
Example:
28 + 17 → __30__ + __20__ = __50__
46 + 31 →
Estimate the sum or difference by rounding to the nearest hundred.
Example:
278 + 137 → __300__ + __100__ = __400__
486 + 341 →
Estimate the sum or difference by rounding to the nearest hundred.
Example:
278 + 137 → __300__ + __100__ = __400__
5,263 − 2,823 →
Estimate the sum or difference by rounding to the leading number.
Example:
278 + 37 → __300__ + __40__ = __260__
24,389 + 4,823 →
