Passive reporting structures

   They _____ countless opportunities for mathematicians.

   _____ that the idea of 'numbers' evolved gradually over time.

 The term 'mathematics' _____ by Pythagoras.

A.  is known to have been invented

B.   has been known to be invented

   The Arabic numeral system _____ to the west from India.

    We _____ the term 'mathematics' was invented by Pythagoras.

 The Arabic numeral system _____ in India.

1     We  _____ algebra originated in ancient Babylonia.

  You are _____ for your exams in the summer.

1     They weren’t _____ in this case.

   Greek mathematics _____ with Thales of Miletus.

 Ancient Egyptians are considered _____ to the development of mathematics.

_____early civilizations developed different ways of writing down numbers.