mental math: doubling and halving
summary
the content focuses on a mental math trick known as doubling and halving, which simplifies multiplication tasks by adjusting the factors in a way that the overall product remains unchanged. this technique is particularly useful for gmat test-takers aiming to enhance their quantitative problem-solving efficiency.
- doubling and halving leverages the associative property of multiplication to simplify calculations by doubling one factor and halving the other without changing the product.
- this method is especially advantageous when one of the factors ends in 5 or 50, making it easier to multiply by converting it into a round number.
- practical examples demonstrate how to apply this trick to perform seemingly complex multiplications quickly in one's head, highlighting its utility in saving time during the gmat quant section.
- the technique can be applied successively, particularly when dealing with factors like 25 or multiples thereof, to further simplify calculations.
- regular practice of this trick can significantly improve mental math skills, making it a valuable strategy for test-takers.
chapters
00:00
introduction to doubling and halving
00:16
applying the trick to simplify multiplication
02:06
when to use doubling and halving
02:53
practical examples and practice problems
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