example 2 predicting results shopping you buy a t-shirt that costs $9.21. you give the clerk $20.00....
TRANSCRIPT
EXAMPLE 2 Predicting Results
ShoppingYou buy a T-shirt that costs $9.21. You give the clerk $20.00. Estimate your change. Is this estimate high or low?
EXAMPLE 2 Predicting Results
$20.00$9.21 –
ShoppingYou buy a T-shirt that costs $9.21. You give the clerk $20.00. Estimate your change. Is this estimate high or low?
EXAMPLE 2 Predicting Results
$20$9 Round 9.21 down to 9.
$20.00$9.21 –
Shopping
–
You buy a T-shirt that costs $9.21. You give the clerk $20.00. Estimate your change. Is this estimate high or low?
EXAMPLE 2 Predicting Results
ANSWER
Your change is about $11. This estimate is high
$20$9 Round 9.21 down to 9.
$20.00$9.21 –
Shopping
–
because you subtracted too little by rounding $9.21to $9.
You buy a T-shirt that costs $9.21. You give the clerk $20.00. Estimate your change. Is this estimate high or low?
EXAMPLE 3 Solve a Multi-Step Problem
You have $10 to buy bread, milk, andGroceries
cereal. If you have enough money, youwould like to buy popcorn. The prices ofthese items are shown. Do you haveenough money to buy popcorn?
SOLUTION
EXAMPLE 3 Solve a Multi-Step Problem
You have $10 to buy bread, milk, andGroceries
cereal. If you have enough money, youwould like to buy popcorn. The prices ofthese items are shown. Do you haveenough money to buy popcorn?
Estimate the sum of all the prices, including the priceof the popcorn.
EXAMPLE 3 Solve a Multi-Step Problem
STEP 1 ADD the front-end digits: the dollars.
EXAMPLE 3 Solve a Multi-Step Problem
STEP 2 ESTIMATE the sum of remaining digits: the cents.
STEP 1 ADD the front-end digits: the dollars.
EXAMPLE 3 Solve a Multi-Step Problem
STEP 3 ADD your results.
STEP 2 ESTIMATE the sum of remaining digits: the cents.
STEP 1 ADD the front-end digits: the dollars.
EXAMPLE 3 Solve a Multi-Step Problem
$1.79
$2.18$3.34$3.65
STEP 3 ADD your results.
STEP 2 ESTIMATE the sum of remaining digits: the cents.
STEP 1 ADD the front-end digits: the dollars.
EXAMPLE 3 Solve a Multi-Step Problem
$1.79
$2.18$3.34$3.65
STEP 3 ADD your results.
STEP 2 ESTIMATE the sum of remaining digits: the cents.
STEP 1 ADD the front-end digits: the dollars.
$9.00
EXAMPLE 3 Solve a Multi-Step Problem
$1.79$2.18$3.34$3.65
STEP 3 ADD your results.
STEP 2 ESTIMATE the sum of remaining digits: the cents.
STEP 1 ADD the front-end digits: the dollars.
$1.79
+
$2.18$3.34$3.65
$9.00
EXAMPLE 3 Solve a Multi-Step Problem
$1
$1
$1.79$2.18$3.34$3.65
STEP 3 ADD your results.
STEP 2 ESTIMATE the sum of remaining digits: the cents.
STEP 1 ADD the front-end digits: the dollars.
$1.79
+
$2.18$3.34$3.65
$9.00
EXAMPLE 3 Solve a Multi-Step Problem
$2
$1.79$2.18$3.34$3.65
STEP 3 ADD your results.
STEP 2 ESTIMATE the sum of remaining digits: the cents.
STEP 1 ADD the front-end digits: the dollars.
$1.79
+
$2.18$3.34$3.65
$1
$1
$9.00
EXAMPLE 3 Solve a Multi-Step Problem
$9$2+
$2
$1.79$2.18$3.34$3.65
$1.79
+
$2.18$3.34$3.65
$1
$1
STEP 3 ADD your results.
STEP 2 ESTIMATE the sum of remaining digits: the cents.
STEP 1 ADD the front-end digits: the dollars.
$9.00
EXAMPLE 3 Solve a Multi-Step Problem
$11
$9$2+
$2
$1.79$2.18$3.34$3.65
$1.79
+
$2.18$3.34$3.65
$1
$1
STEP 3STEP 2 ESTIMATE the sum of remaining digits: the cents.
STEP 1 ADD the front-end digits: the dollars.
ADD your results.
$9.00
EXAMPLE 3 Solve a Multi-Step Problem
Because 11 > 10 you do not have enough money to buy popcorn.
ANSWER
GUIDED PRACTICE for Examples 2 and 3
Use front-end estimation to estimate the sum.6.42 + 7.64 + 3.94 + 2.213.
ANSWER
GUIDED PRACTICE
20
for Examples 2 and 3
Use front-end estimation to estimate the sum.6.42 + 7.64 + 3.94 + 2.213.
GUIDED PRACTICE
Use front-end estimation to estimate the sum.8.59 + 1.37 + 2 + 6.124.
for Examples 2 and 3
ANSWER
GUIDED PRACTICE
18
for Examples 2 and 3
Use front-end estimation to estimate the sum.8.59 + 1.37 + 2 + 6.124.
GUIDED PRACTICE
Use front-end estimation to estimate the sum.How can you estimate the difference in Example 2 sothat your answer is a low estimate?
$20.00$9.21 –
for Examples 2 and 3
GUIDED PRACTICE
Use front-end estimation to estimate the sum.How can you estimate the difference in Example 2 sothat your answer is a low estimate?
Round 9.21 up to 10.
$20.00$9.21 –
$20.00$10.00 –
for Examples 2 and 3
GUIDED PRACTICE
Use front-end estimation to estimate the sum.How can you estimate the difference in Example 2 sothat your answer is a low estimate?
ANSWER
Your change is about 10. This estimate is lowbecause you subtracted too much by rounding 9.21to 10.
Round 9.21 up to 10.
20.00 9.21 –
20.00 10.00 –
for Examples 2 and 3