Question 5 is 54890-0.0002=______. Is this the first use of a trailing 0? Is
this the first time students need to add a 0?
Lesson 2
For multiplication of fractions the book does not do a good job of
explaining cancellation.
Page 28
25/3 : On different calculators you will get different numbers of trailing 3's.
25/3 = 8.333333... where the three dots (...) mean that the pattern continues forever.
Of course, on our calcualtor we can press the
key to get
Lesson 3
negative numbers is just a repeat of earlier material.
Spend time looking at the difference between
and
and then compare that to
and
Lesson 6, page 97
There is no reason given for putting the 1st minute in the
chart at the 50/min rate. You end up with 45 minutes at the standard
rate but that is not justified in the problem statement.
Problem 6, page 109
the measurements are not realistic for an entire house!
Problem 1 answer, page 124
This is wrong...they are treating ft as if it were yds.
Problem 1 on Page 127, answer on Page 129.
This is incomplete because they do not give you enough
information. In particular, "over what time period" is this in effect?
The answer assumes 1 year, but that is not given in the problem. Furthermore,
what do you do with the dividend and interest earned in option 1?
In general
The "tile" problems assume "no waste" and this is not explained. It is not always the
case that we can cut a piece of tile and use both pieces.
The carpet problems do not take into account the width of a roll of carpet. Consider the
problem of ordering enough carpet for a 10 foot by 10 foot room. Unfortunately, carpet comes
in 12 foot wide rolls. We need 100 square feet of carpet, and we could get that by ordering
81/3 feet of the carpet (81/3x12=100). However,
if we did this we would be sewing many pieces together to get our 10x10 shape. More than likely,
we would opt for buying 10 feet (31/3 yards), if we could, and then
cut out the entire 10x10 piece from that.
key to get 
and 
and 