You didn't give any problems,
so I'll make some up. I hope they are
like the ones you were asked to solve.
All rational numbers expressed
as decimals will either terminate
or repeat a block of digits
forever. That's because in long
division all the remainders will
always be less than the divisor,
so sooner or later the remainder
will either be 0 or will be the
repeat of a remainder obtained
earlier.
write the decimal expansions for these
rational numbers. tell whether the
expansions are terminating or repeating.
#1. 9/32
Use long division:
.28125
32)9.00000
6 4
2 60
2 56
40
32
80
64
160
160
0
Terminating because the division
eventually has 0 remainder
#2. 15/22
Again use long division:
.6818
22)15.0000
13 2
1 80
1 76
40
22
18
This is a repeating decimal because the same
non-zero remainder 18 occurred twice in the
long division. These two 18's are indicated in
red above.
--------------------------------------------
Find the rational number equivalents for these
decimal expansions. tell whether they are
rational or irrational
#3. .185185185185···
Let N = .185185185185···
There are 3 digits in the repeating block
"185", so multiply by 103 or
1000
1000N = 185.185185185···
Now place the first equation underneath
and subtract the two equations
1000N = 185.185185185···
N = .185185185185···
999N = 185.000000000
999N = 185
N = 185/999
that reduces to
N = 5/27
This is RATIOnal because it is the
RATIO of two integers
#2. 2.9373737837···
Let N = 2.937373737···
There are 2 digits in the repeating block
"37", so multiply by 102 or
100
100N = 293.737373737···
Now place the first equation underneath
and subtract the two equations
100N = 293.737373737···
N = 2.93737373737···
99N = 290.800000000···
99N = 290.8
Clear of decimals by multiplying thru
by 10
990N = 2908
N = 2908/990
that reduces to
N = 1454/495
This is RATIOnal because it is the
RATIO of two integers
#3. .72772277722277772222···
This is IRRATIONAL because
there is no block of repeating
digits.
--------------------------------------------
simplify the following
radicals.
#4.
#5.
Edwin