MGMAT Flashcards
Unknown Digits Problems
- Be ready to create variables to represent unknown digits.
- Recognize that each unknown is restricted to at most ten possible values (0-9).
- Apply any given constraints, may involve number properties like divisibility or odds & evens.
Powers of 10 & Decimals
- When you multiply by a power of 10, move the decimal right the number of specified places.
- When you divide by a power of 10, move the decimal left.
- Negative powers of 10 reverse the process.
“trading decimal places for powers of ten”
How to find the Last Digit Shortcut
- Drop any digits but the ones unit from all numbers.
- Multiply/add all the ones digits.
- Take the ones digit of the final product.
Why use Heavy Division Shortcut
To solve division problems with complex decimals:
How to use Heavy Division Shortcut
- Set up the division problem in fraction form.
- Rewrite the problem, eliminating powers of 10.
- Get a single digit to the left of the decimal in the denominator.
- Focus on the whole number parts of the numerator and denominator and solve.
- if not precise enough, keep one more decimal place and do long division.
What do you do with the decimal in Addition Subraction
- make sure to line up the decimal points and make decimals the same length.
What do you do with the decimal in Multiplication:
- ignore the decimal until the end.
- multiply and count the total number of digits to the right of the decimal in both factors. Put that many digits in the product.
- if multiplying a very small and large number, move decimals in the opposite direction to make the same number of places.
What do you do with the decimal in Division
- if a decimal In the dividend (inner #), bring the decimal point straight up to the answer and divide.
- if a decimal in the divisor (outer #), shift the decimal point in both the divisor and dividend to make the divisor a whole number. Then divide.
- simplify division by moving decimals in the same direction.
How do you take a power or a root of a decimal
By splitting the decimal into 2 parts: an integer and a power of ten.
the number of decimal places in a cube is HOW MANY TIMES the number of decimals in the original number.
the number of decimal places in a cube is 3x the number of decimals in the original number.
- the number of decimals in a cube root is WHAT FRACTION of the number in the original.
- the number of decimals in a cube root is 1/3 the number in the original.
What are proper fractions
are those that fall between 0 and 1, numerator always smaller than denominator.
What are improper fractions
greater than 1, numerator greater than denominator.
What are mixed numbers
Mixed numbers: written as integer and proper fraction.
What are Complex Fractions
sum or difference in numerator/denominator
For positive fractions,
1. As the numerator increases,
the fraction increases.
For positive fractions,2. As the denominator increases,
the fraction decreases.
For positive fractions,Adding the same number to both the numerator and denominator brings the fraction
closer to 1.