What problem did ancient number systems have?
Early number systems did not have a symbol for nothing. Ancient peoples used a blank space to show an empty place, but this could be confusing, since a blank could easily be overlooked. In India, mathematicians began to treat zero as a number in its own right and described how it behaves in addition and subtraction. Their work reached the Arab world, where scholars in Baghdad studied and expanded it, and later it travelled to Europe. Today the zero is so familiar that it is hard to imagine arithmetic without it, yet it took centuries for it to be accepted as a true number rather than only a placeholder.
Answer and explanation
Correct answer: C. They had no clear symbol for an empty place.
- Step 1: The passage begins by saying early systems had no symbol for nothing and used blank spaces. Step 2. That caused confusion. Answer: They had no clear symbol for an empty place. Why not the others: The passage does not say that digits were missing; writing material is not discussed; Baghdad is mentioned later as a centre of study.
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