Transcript Lesson 1-5a

1-5
6th grade math
Rounding Whole Numbers and
Decimals
Objective
• To estimate and round whole numbers and
decimals.
• Why? To help you understand and
approximate rounding and estimating of
whole numbers and decimals.
California State Standards
NS 1.1 (Gr. 5): Manipulate very large (e.g., millions)
and very small (e.g., thousandths) numbers.
MR 1.0: Make decisions about how to approach
problems.
Vocabulary
• Rounding
- To change a number to the nearest 10, 100, 100,
tenth, hundredth, thousandth, etc.
- Remember any number whose ones digit is between
0 and 4 will not be rounded. But a digits whose
number is between 5 and 9 will be rounded up.
- 44 = 40; 4.67 = 5 or 4.7
• Estimation
To round a number
How to Round Whole Numbers and Decimals
1) Read the directions for what
place value ‘to round to’.
2) Find the place being asked
and underline it.
3) Look to the digit to the right.
4a) If the digit is less than 5,
keep the number the same.
4b) If the digit is more than 5,
round the number up.
5) Keep all the numbers to the
left the same, change or keep
the asked digit, change all
other digits to zeros (0’s).
Round to nearest tenth.
14.77
= 14.77
= 14.80
Round to the nearest hundred.
1,639
= 1,639
= 1,600
Try It!
Round 2,593.6781 to nearest places.
1) Nearest hundred
2)
Nearest thousandths
3)
Nearest tenth
4)
Honolulu’s average rainfall to
nearest ten inches.
1) 2,593.6781
= 2,593.6781
= 2,600.0000
2) 2,593.6781
= 2,593.6781
= 2,593.6780
3) 2,593.6781
= 2,593.6781
= 2,593.7000
4) 22.02
= 20.00 inches
Objective Review
• You can now use To
estimate and round
whole numbers and
decimals.
• Why? You can now approximate whole
numbers and decimals. This will help
you when you are checking for
reasonableness. To round decimals to a
given place, follow the same steps as for
rounding whole numbers. Pay attention
to the given place and the place to its
right in order to round.
Independent Practice
• Complete problems 517
• Copy original problem
first.
• Show all work!
• If time, complete Mixed
Review: 18-23
• If still more time, work
on Accelerated Math.