Whole numbers

Whole numbers

1. 3-01:Rounding and estimating

   • bigger than 5, round up
   • smaller than 5, round down
   • when rounding place value
     • tens
       • look at unit place
     • hundreds
       • look at tens place
     • thousands
       • look at hundreds

2. 3-02 :multiplying numbers

   • 2
     • double once
   • 4
     • x2x2
   • 8
     • x2x2x2
   • 5
     • x10, halve
   • 9
     • x10, - original number
   • 10
     • add a 0
   • 100
     • add 00

3. 3-03 :dividing numbers

   • 2
     • halve
   • quotient
     • answer of a division sum
   • 4
     • double twice
   • 8
     • double 3 times
   • 5
     • divide by 10, x2
   • 10
     • move the decimal point 1 digit to the left
   • 100
     • move the decimal point 2 digits to the left

4. 3-04 :Divisibility tests

   • 2
     • if number is even
   • 3
     • sum of digits is divisible by 3
   • 4
     • last 2 digits form a number divisible by 4
   • 5
     • if last digit is 5 or 0
   • 6
     • divisible by 2 & 3
   • 8
     • last 3 digits form a number divisible by 8
   • 9
     • sum of digits divisible by 9
   • 10
     • If last digit ends in 0

5. 3-05 :Long division

   • is a type of division used to make division with bigger and harder numbers easier.

6. 3-06 :Roman numerals

   • 1=i, 2=ii, 3=iii, 4=iv, 5=v, =vi, 7=vii, 8=viii, 9=ix, 10=x
   • 20=xx, 30=xxx, 40=xl, 50=l, 60=lx, 70=lxx, 80=lxxx, 90=xc, 100=c, 400=cd, 500=d, 1000=m

7. 3-07 :Powers and index notation

   • index notation is used to write repeated multiplication in a easier way
   • example- 8 to the power of 4 (8^4)=8x8x8x8

8. 3-08 square and cube root

   • square root-perfect squares is a number that when you multiply a number by itself number the answer is that- eg:6x6=36, 36 is the squared number, 6 is the square root
   • cube root-perfect squares-is a number that when you multiply a other number tom the power of 3, the answer is that eg:3x3x3=27, 27 is the cubed number, 3 is the cubed root.

9. 3-09 & 3-10 prime and composite numbers & prime factors

   • prime numbers are numbers that are only divisible by 1 and itself
   • 1 is nether prime nor composite
   • composite numbers are numbers that have more than 2 divisors
   • prime factors are numbers that when times together make that number, eg: prime factors of 12 =2x2x3

10. 3-11 & 3-12, Greatest common divisor and lowest common multiple

    • GCD is an easier way to find to find the highest common factor using factor trees
    • LCM is a method to find the lowest number that all of the other numbers go into eg: LCM of 4&3=12