FREE Bachelor of Mathematics: Mathematical Proof and Logic Questions and Answers
what is the trick to subtracting any number from 1000 quickly?
The correct answer is "Subtract each digit from 9 and the last from 10." The trick to rapidly subtracting any number from 1000 involves subtracting each individual digit from 9, except for the last digit, which is subtracted from 10. This technique offers a swift and efficient approach to mental subtraction.
How does the document suggest dealing with percentages?
The correct answer is "Convert them to decimals." The document recommends transforming percentages into decimals as a method of dealing with them. This conversion simplifies calculations and allows for easier comparison and mathematical manipulation.
Which of the following is a way to improve your mental math skills?
The correct answer is "Practice regularly and consistently." Engaging in regular and consistent practice is an effective method to enhance one's mental math skills. By repeatedly working through mathematical problems without solely relying on calculators or shortcuts, individuals can strengthen their ability to perform calculations mentally and improve their overall mathematical fluency.
In multiplication by 11, what rule is applied when the sum of two adjacent digits is more than 9?
The correct answer is "Carry over to the next digit." When multiplying by 11, if the sum of two adjacent digits in the original number is more than 9, the rule of carrying over to the next digit is applied. This involves adding the tens place value from the sum to the next digit and maintaining the units place value of the sum as the digit in the multiplication result.
What method does this document recommend for multiplying two-digit numbers less than twenty but more than ten together?
The correct answer is "Apply cross multiplication while considering tens separately." As advised in the document, when multiplying two-digit numbers between ten and twenty, the method of cross multiplication is suggested, with a focus on treating the tens place value separately. This technique involves multiplying the tens digit of one number with the units digit of the other, and then adding the products.
According to this document, multiplying by 4 can be done faster by doing what instead?
The correct answer is "Multiplying it twice after doubling it." As indicated in the document, a quicker approach to multiplication by 4 involves first doubling the number and then multiplying the result by 2 again. This technique simplifies the process and reduces the number of operations required.
What method does this document suggest for squaring numbers ending in 5?
The correct answer is "Multiply the first digit(s), before five, with its successor number and append '25'." when squaring numbers ending in 5, you multiply the digit(s) before the 5 by the number that comes after it (its successor), and then append "25." This technique provides a quick method for calculating the square of numbers ending in 5.