Fundamentals of Mathematics, 2008a

377
Display Reads
Type .8215199 0.8215199
Press ÷ 0.8215199
Type 4.113 4.113
Press = 0.1997373
Table 6.24
There are EIGHT DIGITS DISPLAY FILLED! BE AWARE OF POSSIBLE APPROXI-
MATIONS.
3
We can check for a possible approximation in the following way. Since the division 4)12 can be
checked by multiplying 4 and 3, we can check our division by performing the multiplication
4.113
} {{ }
3 decimal
places
× 0.1997373
} {{ }
7 decimal
places
This multiplication produces 3 + 7 = 10 decimal digits. But our suspected quotient contains only 8
decimal digits. We conclude that the answer is an approximation. Then, rounding to ve decimal
places, we get 0.19974.
6.7.5.2 Practice Set C
Find each quotient using a calculator. If the result is an approximation, round to four decimal places.
Exercise 6.7.12 (Solution on p. 411.)
42.49778 ÷ 14.261
Exercise 6.7.13 (Solution on p. 411.)
0.001455 ÷ 0.291
Exercise 6.7.14 (Solution on p. 411.)
7.459085 ÷ 2.1192
6.7.6 Dividing Decimals By Powers of 10
In problems 4 and 5 of Section 6.7.4.2 (Practice Set B), we found the decimal representations of 8, 162.41÷10
and 8, 162.41 ÷ 100. Let's look at each of these again and then, from these observations, make a general
statement regarding division of a decimal number by a power of 10.
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