3. Basics – Addition, Multiplication, Subtraction and Division




Most people understand the basics – here we're going to enhance your knowledge and think about things in the bigger picture.

Number types:

Even/Odd

Even +/- Even = Even

Even +/- Odd = Odd

Odd +/- Odd = Even

Even x Even = Even

Even x Odd = Even

Odd x Odd = Odd

Prime – greater than 1 and only divisible by 1 or itself only.

Consecutive numbers

Factors Factors of 6 are? 2 and 3. Note well as this isn't shown in the video - that for every number, 1 and itself is a factor. So for 6, a factor of it is also 1 & 6 because 1 x 6 = 6. For 7, it's 1 & 7 because 1 x 7 = 7. 7 is a prime number so it can only be factorised once - by itself and 1.

Multiples Multiples of 6 are? 12, 18, 24.

Negative and Positive numbers

  1. - and + = -
  2. - and - = +
  3. + and + = +
  • If there are 2 signs near each other, change to 1 sign using above rules.
  • If adding 2 numbers with the same sign, keep the sign and add the numbers.
  • If adding numbers with opposite sign, keep the sign of the number furthest from zero then subtract the numbers ignoring the sign.
  • To minus 2 numbers, change minus sign to addition and change the sign of the number being subtracted to its opposite
  • Multiplying and dividing is the same and follows rules 1 to 3 in determining the end sign.

There is an order in which operations should be done which follows this rule.

B rackets O ver D ivisio n M ultiplication A ddition S ubtraction

Let's go through some examples now:

Q36 -(-4)^ 2

A -16 B -12 C 16 D 8 E None of these

Q35

Using the addition pyramid, the number in the box between 5 and 15 at the fourth layer will be

A 15 B 8 C 10 D 20

Q 36 The number in the box between 1 and 2 at the second layer will be

A 0 B 1 C 2 D 3

Which one of the following is a multiple of 2

A 295 B 459 C 716 D 983

-2 + -3 x 2 - -4 = ?

Key Rules to remember:

  • Brackets Over Division Multiplication Addition Subtraction
  • The different types of numbers and their rules
    • Odd/Even
    • Prime
    • Consecutive
    • Factors
    • Multiples
    • Negative and Positive Numbers

Now it's time to do your assignment.

  1. Download the assignment question here.
  2. Print it out or if you want to do it electronically, save it.
  3. Complete the questions to it.
  4. Then check the solutions on the video below or download the ANSWER KEY here.




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