I am new to Electronics and have only just starting to getting a grasp of ohms law, I have been given some basic homework to create a basic circuit on a breadboard and to complete reading with my multimeter , It is very basic and in series and only has three resistors - Volt 6v - 4.7k - 5.1k - 10k, . I have finished setting it up i have also started to learn LTspice sim to also plan it out . now my question is ohms law works great but in the real world not everything is accurate , like my power supply reads 6 volts but when i tested it with my multi meter it read 6.50 volts , also resistors don't always add up to what there rated when i test them with my meter as by there colour code , yes we are only taking about small differences but dose this matter? When i measured the current i got 305.6 uA or 00.30mA reading but the numbers would change from a few digits that the closest i could get , the RT adds up to 19.8 ohms, but when i calculate V x I = 20.00 ohms , Is this normal or am i doing something wrong . With the resistors i went with the rated from the colour code and not from the reading that i tested them, i think the 10k read 9.50 ohms the 5.1k read 5.7 k so you get the idea slightly out of what there ratings say .