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Mental Math: Doubling and Halving

The content focuses on a mental math trick known as doubling and halving, which simplifies multiplication problems in the GRE exam by making calculations easier to manage without a calculator.
  • Doubling and halving leverage the associative property of multiplication, allowing for the re-grouping of factors to simplify calculations.
  • This technique is particularly useful when one of the factors ends in 5 or 50, as doubling these numbers results in a round number, making the multiplication straightforward.
  • Practical examples demonstrate how to apply this trick to different multiplication scenarios, highlighting its utility in making quick and efficient calculations.
  • The trick can be applied successively, especially useful when dealing with factors like 25 or multiples of 25, to further simplify calculations.
  • Emphasizes the importance of practicing this trick to save valuable time during the Quant section of the GRE exam, enhancing test-taking efficiency.
Introduction to Doubling and Halving
Applying the Trick to Simplify Calculations
Practical Examples and Practice Problems
Summary and Importance of the Trick