Week Two - Taite 29th April

Today we looked at substituting numbers into algebraic expressions. When we calculate these numbers we need to follow some rules:

• B - brackets first (inside each bracket use the BEDMAS again)
• E - exponents next (this includes powers and roots)
• DM - division and multiplication go together, if there are both go left to right
• AS - adding and subtracting go together, if there are both go left to right
• Always put brackets around the top and bottom of a fraction
• Always put brackets around a negative number if it has an exponent.
  

e.g. if a = 3, b= 4 and c = -1 then

a) a + b = 3 + 4 = 7
b) 6c = 6 x -1 = -6
c) 2(b+c) = 2 x (4 + -1) = 2 x 3 = 6
d) c^2 = (-1)^2 = 1

Homework: 7.04

Week Two - Turei 27th April

Today we looked at changing words into algebraic expressions, which basically means writing words as algebra.

To do this we need to be aware of different ways of saying plus, minus, times and divide.

e.g. plus, add, more, sum, extra, additional, increase

e.g. minus, subtract, difference, less, decrease, reduce

e.g. times, multiply, "of" (like groups of or lots of), double/twice (only for x2)

e.g. divide, split, share, halve (only for division by 2)

We then need to work out what the words would mean in terms of the symbols and numbers.

e.g. I have $p in my bank. What would I have if I:

• spent $12 ---> this would give p - 12 as the money has left the account
• banked $50 ---> this would give p + 50 as I have more money in the account
• doubled my money ---> would give 2p which means two times p
• spent $q ---> p - q

Homework: 7.01 & 7.02

Remember your lines for tomorrow!

Week Two - Mane 26th April

Today we began looking at algebra. In algebra we use letters to represent numbers we don't know (unknowns) or numbers that can change (variables). We have rules about how we write things in algebra:

• We don't write x, instead we put letters right adjacent to numbers e.g. 2y
• Numbers always come first then letters in alphabetical order e.g. 3pqr
• instead of a divide sign we use a fraction e.g. 8/x

Homework: 6.8-6.10 (since I forgot to tell you about this on Friday)

Week One - Paraire 24th April

Today we looked at using standard form to represent small numbers. This is the same as for large numbers except we use negative powers to show the decimal point moves in the opposite direction.

Homework: 6.8 - 6.10

Next week we begin algebra.

Week One - Thursday 22nd April

Today we looked at representing numbers in standard form. This is a special way of writing a number that is useful for very big or very small numbers. There are 3 steps:

1. Move the decimal point in the number to straight after the first digit. e.g 3002 becomes 3.002, 74.8 becomes 7.48, and 5.89 stays as 5.89
2. Count the number of places the decimal point has moved, in the examples above this is 3 (remember a decimal point is always at the end of a whole number), then 1 and then 0.
3. The number in standard form is then the new number multiplied by 10 to the power of the number of places moved.

e.g. 3002 = 3.002 x 10^3
74.8 = 7.48 x 10^1
5.89 = 5.89 x 10^0

Homework: 6.04 and 6.05

Week One - Tuesday 20th April

Welcome to the class Shannon.

Today we looked at rounding using decimal places (dp) or significant figures (sf). The rules for both are the same:

1. Count how many sf or dp you want to keep.
2. Circle the next number.
3. If this number is 0,1,2,3 or 4 then drop the circled number and everything to the right. (Stay the same). If this number is 5,6,7,8 or 9 then round the number before up by one, and then drop. (Round up)
4. For sf you may need to add zeros because the rounded number should be close to the original number.

Homework: 6.02 and 6.03

Term Two - Week One - Monday 19th April

WELCOME BACK!

Today we found out what significant figures are. These are:

• any digit (before or after decimal point) from 1-9
• any zeros between numbers from 1-9
• any zeros that are BOTH at the end of the number AND after the decimal point, and the zeros leading up to this one

e.g. 30.8 has 3sf since the zero is between numbers.

e.g. 10000 has 1sf since the zeros are not between or after a decimal point. BUT sometimes when we say 10000 we mean exactly 10000, not about 10000. If that is the case all the numbers are significant, so it has 5sf.

e.g. 0.0038 has 2sf since the zeros are not between or at the end of the number.

e.g. 0.020700 has 5sf. the first two zeros are not counted. The next one is because it is between, and the last two are because they are at the end and after the decimal point.

Homework: ex 6.01