Rounding and Estimating
Standard
7.N.1 Compare, order, estimate, and translate among integers, fractions and mixed numbers,decimals,and percents.
Cluster
C10
Vocabulary
Decimal-a number that is written using the base-ten place value system where the decimal point separates the ones' and tenths' digits.
Objective
To round decimals
To estimate sums and differences
Lesson
Rounding Decimals
If the number is 5 or greater round up
If the number is 4 or lower round down.
Ex
4.2683 To round this number to the tenths place, you would look at the number to the right. It is greater than 5 so you would round up
4.3
Ex.
4.231 To round this number to the hundredths place, you would look at the number to the right. It is less than 5 so you would round down.
4.23
Estimating Sums or differences
Use front end estimation to round to the nearest whole then add or subtract
Ex. 135.95 + 15.90 + 24.05
135.95 is close to 140
15.90 is close to 16
24.05 is close to 24
then add
140 + 16 + 24 = 180
Ex 37.99 - 27.32
37.99 is close to 37
27.32 is close to 27
Then subtract
37 - 27 = 10
