To find out how many words Callum can read per minute, you need to divide the total number of words he can read by the total number of minutes.
Callum can read 120 words in 3 minutes.
To find the number of words he can read in one minute, you can calculate:
\[ \text{Words per minute} = \frac{\text{Total Words}}{\text{Total Minutes}} = \frac{120 \text{ words}}{3 \text{ minutes}} = 40 \text{ words per minute} \]
So, Callum can read 40 words per minute.