- PLUMBING BILLS A corner of the invoice for
plumbing work is torn. What is the labor charge for
the 4 hours of work? What is the total charge
(standard service charge, parts, labor)?
- WEIGHTLIFTING The barbell is evenly loaded
with iron plates. How much plate weight is loaded
on the barbell?
- SWIMMING POOLS Long bricks, called coping,
can be used to outline the edge of a swimming pool.
How many meters of coping will be needed in the
construction of the swimming pool shown?
- STORM DAMAGE After a rainstorm, the
saturated ground under a hilltop house began to
give way. A survey team noted that the house
30.3 m
50 m
45.5 lb
20.5 lb
2.2 lb
Carter Plumbing
100 W. Dalton Ave.
Invoice
#210
Standard service charge $ 25.75
$
$
$
Parts 38.75
Labor:
4 hr @ $40.55/hr
Total charges
dropped 0.57 inch initially. In the next three weeks,
the house fell 0.09 inch per week. How far did the
house fall during this three-week period?
- WATER USAGE In May, the water level of a
reservoir reached its high mark for the year. During
the summer months, as water usage increased, the
level dropped. In the months of May and June, it fell
4.3 feet each month. In August, and September,
because of high temperatures, it fell another 8.7 feet
each month. By the beginning of October, how far
below the year’s high mark had the water level
fallen?
WRITING
- Explain how to determine where to place the
decimal point in the answer when multiplying two
decimals.
- List the similarities and differences between whole-
number multiplication and decimal multiplication.
- Explain how to multiply a decimal by a power of 10
that is greater than 1, and by a power of ten that is
less than 1.
- Is it easier to multiply the decimals 0.4 and 0.16 or
the fractions and? Explain why.
- Why do we have to line up the decimal points when
adding, but we do not have to when multiplying?
- Which vertical form for the following multiplication
do you like better? Explain why.
REVIEW
Find the prime factorization of each number. Use exponents in
your answer, when helpful.
- 220 126. 400
- 162 128. 735
2.8
0.000003
0.000003
2.7
16
100
4
10
4.3 Multiplying Decimals 357
