H is equal to 8
M is equal to 15.3
20-12= 8
9+6.3= 15.3
Hope this helped
Multiplication is a simple way of adding
For example 6x8 is the same as 8+8+8+8+8+8
Any number multiplied by 1 is itself E.g 4x1 = 4
Multiplying by 2 is just doubling
Multiplying by 10 is adding a 0 to the original number
If it is a big number that you do not know how to multiply mentally split it up
E.g 17x13
Split 13 into 10 and 3
17x10= 170
17x3= 51
Then add these numbers
221
If you ever get stuck, use the long method, add them instead, you will get to the right answer but it will take longer
Dividing is not as simple
Like multiplication dividing by one will leave you with the same answer
Dividing by two means you half the number, which may give you a decimal
Bigger numbers are trickier, and you may be allowed to use a calculator for numbers
Below are a number of links, these websites will teach you how to improve your multiplication and division skills:
http://www.bbc.co.uk/schools/gcsebitesize/maths/number/decimalsrev3.shtml
https://m.youtube.com/watch?v=XiXeu9FxAcQ
https://www.tutorialspoint.com/multiply_and_divide_whole_numbers/multiplication_as_repeated_addition.htm

Differentiate both sides with respect to

:

When

, you have

For part (b), we now assume that

and

are functions of an independent variable, which we'll call

(for time). Now differentiating both sides with respect to

, we have

where the chain rule is used on the right side. We're told that

is decreasing at a constant rate of 0.1 units/second, which translates to

. So when

, you have



where the unit is again units/second.
8 - sqrt(3) is indeed the conjugate of 8 + sqrt(3).
What are you asking here? You are to "evaluate or simplify" what?
If rounding to the hundreds
To estimate round 324 and 285 to the closest hundred.
300 - 300
Then subtract 300 - 300 =
0
If rounding to the tens
To estimate round 324 and 285 to the nearest ten.
320 - 290
Then subtract 320 - 290 =
30