A resistor is identified by its pattern of color of bands. There are 4, 5 and 6 band resistors ... So according to the formula the resistance will be: 152 * 1 = 152 Ohms with 5% tolerance.
He came up with Ohm Sense, an iPhone app that will take a picture of a resistor and calculate the value based on the color bands. It’s a great tool that we wish we had when we were starting out.
Let’s take an example of a 4-band resistor with the colors given in the above image (brown, blue, red and gold). So according to the formula the resistance will be: 16 * 100 = 1600 Ohms or 1.6K Ohms ...