Maths

• 2 is the only even prime number
• prime numbers have only 2 factors 1 and itself
• composite numbers is a number that has more than 2 factors
• composite numbers can be arranged in equal rows
• there are 25 prime numbers in the square table
• there are 74 composite numbers in the square table
• Cutting a large roll of cloth into 4-m strips


  1. Check the last two digits of the roll length

  2. Note the roll length

  3. If the last two digits are divisible by 4, then there will be no cloth left over
• There will not be any cloth left after the cutting of a 3728-m roll of cloth
• Packing oranges in boxes of 8

  1. Check the last three digits of the total oranges harvested

  2. If the last three digits are divisible by 8, then there are no oranges left over
• There are oranges left over from 4568 oranges harvested
• Prime number

  A number that has only two factors: 1 and itself
• Factors of 14

  • 2
  • 7
• 14 is a composite number
• Shan has 20 stickers
• Gerald has 1 less sticker than Shan
• 20 stickers can be arranged in equal rows
• 20 is a composite number
• 19 stickers (Gerald's) cannot be arranged in equal rows
• 19 is a prime number
• Composite number

  A number that has more than two factors
• I am a composite number less than 50, with 3 factors, and divisible by 7
• The number is 49
• Creating a basic 3-digit passcode


  1. Multiply a prime number and a composite number

  2. The numbers must be consecutive
• The prime number is 19, the composite number is 33
• There can be more than one set of numbers that satisfy the criteria
• Square number


  A number made by multiplying a number by itself
• Creating a sequence of square numbers


  1. 1st term: 1x1=1

  2. 2nd term: 2x2=4

  3. 3rd term: 3x3=9

  4. 4th term: 4x4=16

  5. 5th term: 5x5=25
• Triangular number


  A number that can be represented by a triangle of dots
• Creating a sequence of triangular numbers


  1. 1st term: 1

  2. 2nd term: 3

  3. 3rd term: 6

  4. 4th term: 10

  5. 5th term: ?
• Each row in the triangular number sequence has 1 more dot than the previous row
• Decimal


  A number written with a decimal point, representing tenths, hundredths, etc.
• Place value table


  A table used to show the value of each digit in a decimal number
• 10 hundredths = 1 tenth
• Rounding a decimal to the nearest whole number


  Round down for 4 tenths or less, round up for 5 tenths or more
• Rounding decimals to the nearest whole number


  • 10.9 rounds to 11
  • 21.2 rounds to 21
  • 28.5 rounds to 29
• • $9.50 rounds to $10.00
  • $4.20 rounds to $4.00
  • $12.80 rounds to $13.00
• Round up for 5 tenths or more


  If the digit in the tenths place is 5 or more, add 1 to the digit in the ones place and remove the decimal point to round up to the nearest whole number.
• Rounding a decimal to the nearest whole number


  1. Identify the tenths place in the decimal. 2. Look at the digit in the tenths place. 3. If the digit in the tenths place is 4 or less, round down to the nearest whole number by removing the decimal point. 4. If the digit in the tenths place is 5 or more, round up to the nearest whole number by adding 1 to the digit in the ones place and removing the decimal point.