Can you help me with this derivatives? Thanks

What is the order of operations for 2 + (3 - 9) ÷ -3 · 4 in number order 1. subtraction 2. division 3. addition 4. multiplication

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?