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Maths Revision (Chapter 4 (Estimation (Uses rounding to find an…

- - - - The numerator must be the same when addig or subtracting proper numbers
      - If not, then find the equavilent fraction of the number
    - - Convert them to improper fractions, then go to page 69 of maths textbook to see the method
  - - - Flip the second fraction, then multiply the numbers
    - - Just multiply the numbers, regardless of denominator
  - - - Same sign
        
        add and keep the sign
      - Different sign
        
        find the difference between the signed numbers, then use the sign of the numbers further from 0
        
        subtract the number, add the opposite
  - - - If not, THEN MAKE IT ONE. multiply the dividend and teh divisor by an appropriate power of 10
      - Then divide teh number as usual, lining up the goddamn points
      - Add extra 0 to teh end if needed
- - - - When multiplying two directed numbers:
        
        if their signs are the same, the answer is a positive
        
        if their signs are different, the answer is a negative.
      - Patterns in the answers in multiplication tables can be used to determine the product when two directed numbers are multiplied
    - - calculating powers of negative numbers uses the same process as calculating powers of positive numbers.
      - There are two possible answers when you take the square root of a number. For example: 4^2= 4 4.=16 (-4)^2= (-4) (-4) = 16
  - - - Division is the inverse operation of multiplication. We can use the multiplication facts for the directed numbers to discover the division facts for directed numbers.
      - When dividing two directed numbers:
        
        if their signs are the same, the answer is positive.
        
        if their signs are different, the answer is negative.
    - - +/+ = +
      - +/- = -
      - -/- = +
      - -/+ = -
  - - - The mathematical rules about order of operation apply when we work with directed numbers.
      - BIDMAS helps us to remember the correct order in which we should perform the various operations. This means we do the brackets (B) first; then indices (I); then division (D) and multiplication (M), working from left to right; and finally addition (A) and subtraction (S), working from left to right.