It is a test required for a Master degree (especially from schools in the US, CANADA and EUROPE)
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The analytical Writing tests measure your critical thinking and analytical writing skills.
The GRE verbal section places premium on vocabulary. Learning words in context gives you a better shot at acing the GRE than merely rote-learning the definition of words.
This is the MATH section of the GRE. Unlike the GMAT where no calculator is either provided or allowed, an on-screen calculator is available for use in the GRE.