Binary and decimal question?

Question

Suppose that i have no calculator and without this method(1*2^6+1*2^5+1*2^4+....) How can i understand whats the decimal of this binary :1100100 just a look.Do you know any tricks or easy way?

Answer 1

Memorize the table of powers of 2 from 0 to 10 or 16.

If you have a zero don't do nothing. If you have a one add the power of 2 for the position (position starts from zero).

For example:

10
first zero add nothing. 1 in position 1. so 2^1 = 2
So 10 = 2

110
position 0. its a zero adds nothing.
position 1. 2^1 adds 2
position 2. 2^2 adds 4

110 = 6

Answer 2

to convert a binary number to its decimal equivalent, you need to apply the formula u specified. but with practice, you can memorize the decimal values corresponding to the binary positions.

1 1 0 0 1 0 0
64 32 16 8 4 2 1

so, wherever there is a 1, you keep on adding. so, the answer would be 64+32+4=100

Answer 3

just memorize the following sequence. write binary numbers on top, pick the numbers under 1's and add them

1 1 0 0 1 0 0
64 32 16 8 4 2 1

64+32+4

100

hope you can do this without calculator

Answer 4

1100100

256 128 64 32 16 8 4 2 1

0 means don't count and 1 means count so.........

4+32+64
= 100

Answer 5

Remember -- binary -- on or off. One or zero. Okay... imagine you have only one hand and only one finger on that one hand. To express the number 1, you'd hold up 1 finger... how would you express the number 10?

Answer 6

divide by 1200

Answer 7

start from here: http://en.wikipedia.org/wiki/Binary_numeral_system