computer science - calculating max and min expressible values for floating point number rep -

I should know IEEE floating-point numbers have a standard like 10 ^ 38 - -10 ^ 38 (and corresponding + Ve) Most textbooks just make this statement of this fact, why not bother with IM, ie How would you do this limit?

Thank you

-prisisn (32-bit) floating point presentation format In, the exponent maximum value is 127. The representation is 2 basis, thus the maximum possible value is approximately 2 ^ 127. Let's: 127 * log (2) / log (10) ≈ 38.23 This is why the maximum value represented by 32-bit float is approximately 10 ^ 38. You can find more details on the IEEE 754 Floats in the linked Wikipedia article.