2.6 Order of Operations and Estimation 191
- THE FEDERAL BUDGET See the graph below.
Suppose you were hired to write a speech for a
politician who wanted to highlight the improvement
in the federal government’s finances during the
1990s. Would it be better for the politician to talk
about the mean (average) budget deficit/surplus for
the last half of the decade, or for the last four years
of that decade? Explain your reasoning.
106. ESTIMATION Quickly determine a reasonable
estimate of the exact answer in each of the following
situations.
a. A submarine, cruising at a depth of feet,
descends another 605 feet. What is the depth of
the submarine?
b. A married couple has assets that total $840,756
and debts that total $265,789. What is their net
worth?
c. According to pokerlistings.com, the top five
online poker losses as of January 2009 were
$52,256; $52,235; $31,545; $28,117; and $27,475.
Find the total amount lost.
WRITING
- When evaluating expressions, why is the order of
operations rule necessary?
- In the rules for the order of operations, what does
the phrase as they occur from left to rightmean?
- Explain the error in each evaluation below.
a.
b.
- Describe a situation in daily life where you use
estimation.
REVIEW
- On the number line, what number is
a. 4 units to the right of?
b. 6 units to the left of 2?
- Is 834,540 divisible by: a. 2 b. 3 c. 4
d. 5 e. 6 f. 9 g. 10
- ELEVATORS An elevator has a weight capacity of
1,000 pounds. Seven people, with an average weight
of 140 pounds, are in it. Is it overloaded?
- a. Find the LCM of 12 and 44.
b. Find the GCF of 12 and 44.
7
35
70 50
1 804 90 1 80 50
10
80 (2)4 80 (8)
175
Deficit Year Surplus
–164 1995
1996
1997
1998
1999
+70
+123
–107
–22
U.S. Budget Deficit/Surplus
($ billions)
- SCOUTING REPORTS The illustration below
shows a football coach how successful his opponent
was running a “28 pitch” the last time the two teams
met. What was the opponent’s mean (average) gain
with this play?
Play:_________^28 pitch
Gain 16 yd
Gain 4 yd
Gain 10 yd
Loss 4 yd
Loss 2 yd
TD
Gain 66 yd
No gain
Loss 2 yd
- ESTIMATION Quickly determine a reasonable
estimate of the exact answer in each of the following
situations.
a. A scuba diver, swimming at a depth of 34 feet
below sea level, spots a sunken ship beneath him.
He dives down another 57 feet to reach it. What
is the depth of the sunken ship?
b. A dental hygiene company offers a money-back
guarantee on its tooth whitener kit. When the kit
is returned by a dissatisfied customer, the
company loses the $11 it cost to produce it,
because it cannot be resold. How much money
has the company lost because of this return
policy if 56 kits have been mailed back by
customers?
c. A tram line makes a 7,891-foot descent from a
mountaintop in 18 equal stages. How much does
it descend in each stage?
