Noise on analog pins on arduino motor shield R3 on arduiono UNO

actually working on ldr robot , taking inputs analog pins pm arduino motor shield r3,i found values lying between 0 100. when checked analog pins without ldr sensor connected arduino saw values 500 on pins (a0 a5).

i frustated , find no solutions.i doubt if because of noise in motor shield circuitry arduino uno r3 alone not show such happenings.

please help???/ 

does mean you're measuring analog inputs without connected? in case you're measuring floating pin gives quite random reading. if want have 0 reading connect analog input gnd , read again.

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