Choose exam board for KS4 Computer Science (GCSE)
Choose exam board for KS4 English
Choose exam board for KS4 French
Choose exam board for KS4 Geography
Choose exam board for KS4 German
Choose exam board for KS4 History
Choose tier for KS4 Maths
Choose exam board for KS4 Music
Choose exam board for KS4 Physical education (GCSE)
Choose exam board for KS4 Religious education (GCSE)
Choose exam board for KS4 Spanish

      Using the fx-83/85GT CW for number

      Lesson details

      Learning outcome

      I can use the fx-83/85GT CW to perform calculations with numbers.

      Key learning points

      1. Some calculators can perform more than just basic calculations.
      2. The fx-83/85GT CW can convert between different formats for values.
      3. The fx-83/85GT CW can quickly calculate the LCM or HCF for a pair of positive integers.

      Keywords

      • Factor - A factor is a term which exactly divides another term.

      • Prime factors - Prime factors are the factors of a number that are, themselves, prime.

      • Lowest common multiple (LCM) - The lowest common multiple is the lowest number that is a multiple of two or more numbers.

      • Highest common factor (HCF) - The highest common factor of two or more integers which can be divided by all other possible common factors.

      • Recurring decimal - A recurring decimal is one that has an infinite number of digits after the decimal point.

      Common misconception

      Calculators can only be used to add, subtract, multiply or divide.

      They can be used to perform basic calculations but they can also do so much more.

      Teacher tip

      For more support with using the Casio fx-83/85GT CW, please visit the Casio website where there are more free resources and interactive guides to support use of this model.

      Equipment

      Casio fx-83/85GT CW

      Licence

      This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0
      except where otherwise stated. See Oak's terms & conditions
      (Collection 2).

      Lesson video

      Loading...

      Prior knowledge starter quiz

      6 Questions

      Q1.
      A is a term which exactly divides another term.

      Correct Answer: factor

      Q2.
      The lowest multiple is the lowest number that is a multiple of two or more numbers.

      Correct Answer: common

      Q3.
      The common factor of two or more integers which can be divided by all other possible common factors.

      Correct Answer: highest

      Q4.
      A decimal is one that has an infinite number of digits after the decimal point.

      Correct Answer: recurring

      Q5.
      What is the LCM of 5 and 6?

      15
      Correct answer: 30
      45
      60

      Q6.
      What is the HCF of 128 and 428?

      2
      Correct answer: 4
      6
      8
      12

      6 Questions

      Q1.
      What does inputting a mixed number into the calculator and pressing ‘EXE’ return?

      The same value but as a decimal
      The same mixed number
      Correct answer: The same value but as an improper fraction

      Q2.
      Which button is used to change freely between improper fractions and mixed numbers?

      CATALOG
      Correct answer: FORMAT
      FUNCTION
      TOOLS
      VARIABLE

      Q3.
      Which of these shows the number 2 227 500 expressed in prime factor form?

      $$2^2 \times 3^2 \times 5^4 \times 11$$
      $$2^2 \times 3^2 \times 5^6 \times 11$$
      Correct answer: $$2^2 \times 3^4 \times 5^4 \times 11$$
      $$2^2 \times 3^4 \times 5^4 \times 11^2$$

      Q4.
      The calculator refers to the HCF as:

      ABF
      Correct answer: GCD
      HCF
      FCB

      Q5.
      State the LCM of 22 and 24.

      Correct Answer: 264

      Q6.
      State the HCF of 3924 and 9741.

      Correct Answer: 3

      To help you plan your 9 maths lesson on: Using the fx-83/85GT CW for number, download all teaching resources for free and adapt to suit your pupils' needs...