example 1 biking the map shows biking times for a trail. estimating sums and differences
TRANSCRIPT
EXAMPLE 1
Biking The map shows biking times for a trail.
Estimating Sums and Differences
EXAMPLE 1
Biking The map shows biking times for a trail.
a. Estimate how long it takes to bike from the trailhead to the swinging bridge and then to the waterfall.
Estimating Sums and Differences
EXAMPLE 1
Biking The map shows biking times for a trail.
a. Estimate how long it takes to bike from the trailhead to the swinging bridge and then to the waterfall.
b. The biking time from the swinging bridge, past the waterfall, to the trailhead is 208 minutes. Estimate the number of minutes it takes to bike from the waterfall to the trailhead.
Estimating Sums and Differences
EXAMPLE 1
SOLUTION
a. Round the two times to the same place value. Then add.
Estimating Sums and Differences
EXAMPLE 1
SOLUTION
a. Round the two times to the same place value. Then add.
28+ 114
Estimating Sums and Differences
EXAMPLE 1
SOLUTION
a. Round the two times to the same place value. Then add.
28+ 114
Round each number to the nearest ten.
Estimating Sums and Differences
EXAMPLE 1
SOLUTION
a. Round the two times to the same place value. Then add.
28+ 114
Round each number to the nearest ten.
30110
Round 28 up to 30.
Round 114 down to 110.+
Estimating Sums and Differences
EXAMPLE 1
SOLUTION
a. Round the two times to the same place value. Then add.
28+ 114
Round each number to the nearest ten.
30+ 110
140
Estimating Sums and Differences
Round 28 up to 30.
Round 114 down to 110.
EXAMPLE 1
SOLUTION
a. Round the two times to the same place value. Then add.
28 Round each number to the nearest ten.
ANSWER: It takes about 140 minutes to bike from the trailhead to the swinging bridge and then to the waterfall.
Estimating Sums and Differences
+ 11430
+ 110
140
Round 28 up to 30.
Round 114 down to 110.
EXAMPLE 1
208- 114
b.
Estimating Sums and Differences
EXAMPLE 1
208- 114
Round each number to the nearest hundred.
b.
Estimating Sums and Differences
EXAMPLE 1
208- 114
Round each number to the nearest hundred.
200- 100
Round 208 down to 200.
Round 114 down to 100.
b.
Estimating Sums and Differences
EXAMPLE 1
208- 114
Round each number to the nearest hundred.
b.
200- 100
100
Estimating Sums and Differences
Round 208 down to 200.
Round 114 down to 100.
EXAMPLE 1
Round each number to the nearest hundred.
ANSWER: It takes about 100 minutes to bike from the waterfall to the trailhead.
b.
208- 114
200- 100
100
Estimating Sums and Differences
Round 208 down to 200.
Round 114 down to 100.
GUIDED PRACTICE for Example 1
Estimate the sum or difference.
27 641.
GUIDED PRACTICE
Estimate the sum or difference.
1.
ANSWER 90
for Example 1
27 641.
GUIDED PRACTICE
Estimate the sum or difference.
180 9142.
for Example 1
GUIDED PRACTICE
Estimate the sum or difference.
2.
for Example 1
180 9142.
ANSWER 1100
GUIDED PRACTICE
Estimate the sum or difference.
91 493.
for Example 1
GUIDED PRACTICE
Estimate the sum or difference.
3.
ANSWER 40
for Example 1
91 493.
GUIDED PRACTICE
Estimate the sum or difference.
612 834.
for Example 1
GUIDED PRACTICE
Estimate the sum or difference.
4.
ANSWER 530
for Example 1
612 834.