1.1 Getting Close: Estimating Sums
When adding or subtracting, it is always a good idea to
exact answer
estimate. The _________________________________ should be close
estimate
to the ____________________________.
A reference number that can be used to estimate the size of
benchmark
other numbers is called a ___________________________.
Is
1
4
+
1
3
+
1
2
less than 1 or greater than 1? How do you know?
Explain your answer in a complete sentence.
the sum is greater than 1 because
equal to
3
4
and since
1
3
is bigger than
1
4
+
1
2
is
, the
1
4
sum is greater than 1 whole
When estimating the sum or difference with fractions and
decimals
fractions
decimals, you can change the ______________ to ______________
fractions
decimals
or the ______________ to ____________ so that you are estimating
numbers in the same form!
Problem 1.1 Study Guide
The Most Important Thing to Know About Fractions!
1
2
3
4
5
6
<
<
<
< < . . . ..
2
3
4
5
6
7
Estimate each sum or difference.
[a.]
5
6
+1
3
10
[b.]
51
100
+
6
10
≈1+1
estimate: 2
[c.]
1
15
− 0.04
≈0+0
estimate: 0
≈
1 1
+
2 2
estimate: 1
[d.] 0.6 −
1
10
≈
1
+0
2
estimate:
1
2
Study Tip: Be sure you can estimate sums or
differences of fractions and decimals!