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Page 449
That is, eight asterisks and seven. That would be represented in base eight as 178. That is, one eight and seven ones.
Around the Bases
You can represent the number fifteen in base ten as 1510, in base nine as 169, in base 8 as 178, in base 7 as 217. Why 217? In base 7 there is no numeral 8. In order to represent fifteen, you will need two sevens and one 1.
How do you generalize the process? To convert a base ten number to base 7, think about the columns: in base 7 they are ones, sevens, forty-nines, three-hundred forty-threes, and so on. Why these columns? They represent 70, 71, 72, 74, and so forth. Create a table for yourself:
4
3
2
1
73
72
71
70
343
49
7
1

The first row represents the column number. The second row represents the power of 7. The third row represents the decimal value of each number in that row.
To convert from a decimal value to base 7, here is the procedure: Examine the number and decide which column to use first. If the number is 200, for example, you know that column 4 (343) is 0, and you don't have to worry about it.
To find out how many 49s there are, divide 200 by 49. The answer is 4, so put 4 in column 3 and examine the remainder: 4. There are no 7s in 4, so put a zero in the sevens column. There are 4 ones in 4, so put a 4 in the 1s column. The answer is 4047.
To convert the number 968 to base 6:
5
4
3
2
1
64
63
62
61
60
1296
216
36
6
1

There are no 1296s in 968, so column 5 has 0. Dividing 968 by 216 yields 4 with a remainder of 104. Column 4 is 4. Dividing 104 by 36 yields 2 with a remainder of 32. Column 3 is 2. Dividing 32 by 6 yields 5 with a remainder of 2. The answer therefore is 42526.
5
4
3
2
1
64
63
62
61
60
1296
216
36
6
1
0
4
2
5
2

 
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