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Base Numbers: Level 1

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Base numbers: 

Convert other bases to base 10. 
Example #1:  
 1  | 0 |0
 22|21 |20                  0*20 + 0*21 + 1*22 = 4

Thus, 1002  = 4 in base 10

The first few base 2 (or binary system) numbers that are equivalent to their base 10 (or decimal) counterpart.
 
base 2                       base 10

0                               0

1                               1

10                             2

11                             3

100                           4

101                           5

110                           6

111                          7

1000                         8

1001                         9

1010                       10    

Example #2:
 
1|  2|  45    
52|51|50                    4*50+ 2*51 + 1*52  = 4 + 10 + 25 = 39 

Thus, 1245 = 39 in base 10   

Some important points: 
 
* All the digits in the number has to be smaller than the base. (Why?)
* Hexadecimal is base 16. In that system, you can use numbers from "0" to "9", the same as base 10.
  However, numbers 10 to 15, you use letters: A for 10, B for 11, C for 12, D for 13, E for 14 and last, F      for 15. 

Short cut to some base conversions:

 #1: Convert 11011112to base 8.

Since 8 = 23, you can convert base 2 to base 8 by regrouping every 3 digits.
Thus the original number will become 1578
because if you regroup the original number starting from the right, you have 12-1012-1112and it's 157 in base 2's term.

#2: Try convert 111100112to base 4, which is 22 so you regroup by 2.

11 (3 in base 2)-11(3 in base 2)-00 (0 in base 2)-11(3 in base 2) so the answer is 33034. 

Convert a number from base 10 to any other base

Here is a link to help you practice more of bases conversion.
 
Practice Problems: (answers below)

Convert other bases to base 10.
#: 101112                                           
#23304
#31005 
#42103
#5246
#6: Convert10111 to base 4 
#7: Convert 123321to base 16 (or hexadecimal) [student Andrew's problem]
#8110100112  is what to base 16 ?
#9Convert1648 to binary (or base 2) [Daniel's question]
#10: What is 100005  minus 15 ? [Remaining :Willie's questions]
#11: What is0.18to base 10?
#12: What is 5378  divided by 108 ?
#13: 3716  is what in base 4? what in base 10?
 

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