LESSON THREE: 12 FEBRUARY 2021

GRADE 9 MATHEMATICS

GRADE 8 REVISION: INTEGERS AND EXPONENTS

Good day Dear Grade 9 Learners.

Please refer to the file called lesson 2 answers. This is so that you can mark your work from Wednesday. Please make sure that it is marked in pencil and that corrections are done. If you have any questions, make note of them and we can discuss them in class.

TODAY’S LESSON

Please recap on integers. We had discussed the various rules with Integers.

·         Integers are positive and negative numbers, including zero.

           ·         Zero is neither positive nor negative.

           ·         When we talk about ADDITION OR SUBTRACTION, if the signs are the SAME, KEEP AND ADD. If the signs are DIFFERENT, USE THE SIGN OF THE LARGER NUMBER, AND FIND THE DIFFERENCE IN THE NUMBERS.

          ·         When we talk about MULTIPLICATION AND DIVISION , IF THERE ARE LIKE SIGNS THE ANSWER WILL BE POSITIVE AND UNLIKE SIGNS THE ANSWERS ARE NEGATIVE .

EXPONENTS

Instead of writing 3 × 3 × 3 × 3 × 3 × 3 we can read this as “3 to the power of 6”. The number 3 is the base, and 6 is the exponent. When we write 3 × 3 × 3 × 3 × 3 × 3 as 36, we are using exponential notation.

LAWS OF EXPONENTS

     ·         MULTIPLICATION LAW   If the bases are the same, add the exponents.

     ·         DIVISION LAW   If the bases are the same, subtract the exponents.

     ·         RAISING A POWER TO A POWER      In this case, we take the inside exponent and multiply it with the outside exponent.

     ·         THE POWER OF ZERO      Any base to the power of zero = 1

     ·         THE POWER OF ONE       Any base to the power of one = the exponent does not have to be shown.

WHAT YOU NEED TO DO:

         1.      In your exercise book, please put in today’s lesson details:
 12 February 2021

        2.      There are two exercises attached. One is on integers and the other is on exponents. Please answer these in your book for today’s date.

Please remember that all the work is to be done in your exercise books. When you return to school, your teachers will expect to see it completed and marked.

______________________________________________________________________END!!!

LESSON COMPILED BY H. MAHARAJ (hmaharaj@alexhigh.org.za)