The teacher and students read a summary of the telephone number (sequential number to read them one at a time, or if there are duplicate numbers and are pedestrians are read as one double or read the sort.)
Teachers and students read the phone number. (Read the numbers in sequence at a time. If you have duplicate numbers and close together to read a double or order one at a time).
Teachers and students were reading the phone number. (read the numbers are respectively arranged one by one. If the numbers are unique and close to read is a sort double or read one by one.) .