Vibrations and Waves

While the concepts of vibrations and waves are becoming more clear, the way to determine the range of wavelengths still remains pretty difficult. Clearly, the formula representing velocity equals wavelength times frequency (v=wavelength*f) would be used, but coming up with a plausible answer is still difficult. Here's an example from the book Holt Physics, of the type of problem which I find puzzling: A piano emits frequencies that range from a low of about 28Hz to a high of about 4200 Hz. Find the range of wavelengths in air attained by this instrument when the speed of sound is 340 m/s. I figured that f1= 28 and f2=4200; v=340, making wavelenth=? I tried plugging these numbers into the formula (340=28*x and 340=4200*x) and came up with 150m and .99m, which do not make much sense. Any ideas on what I am doing incorrectly.