Melody

$$7\pm8=7+8\;\;OR \;\;7-8\\\\
$So there are two answers, 15 and -1 are both correct answers, you need BOTH of them to make a whole answer! $$$

Look Dragon

$$aaaa * aaaaa =a*a*a*a * a*a*a*a*a = a^9$$

What shape is this fish tank?  It is a bit confusing.

thanks quinn,

We might try it this way.

$$\frac{5}{6}\div \frac{7}{12}\\\\
=\frac{5}{6}\times \frac{12}{7}\\\\
=\frac{5}{\not{6}^1}\times \frac{\not{12}^2}{7}\\\\
=\frac{10}{7}\\\\
=1\frac{3}{7}\\\\$$

Dragon, you wrote that before you even had time to think about what I had written!!!

Now go back and think about it properly!

The diameter of a circle is the line that goes all the way across from one side to the other and it passes through the centre.

Hi Dragon  

$$a^2b-7\frac{a^2}{a^5}\\\\
a^2b-\frac{7}{1}\times\frac{a^2}{a^5}\\\\
a^2b-\frac{7\times a^2}{1\times a^5}\\\\
a^2b-\frac{7a^2}{a^5}\\\\
a^2b-\frac{7aa}{aaaaa}\\\\
a^2b-\frac{7\not{a}\not{a}}{\not{a}\not{a}aaa}\qquad \mbox{Note: aa cancels out}\\\\
a^2b-\frac{7}{aaa}\\\\
a^2b-\frac{7}{a^3}\\\\$$

Halley

0.11 is 9 times smaller than 0.99

They are not close at all !      :)

$$\\(\textcolor[rgb]{0,1,0}{2a}\textcolor[rgb]{0,0,1}{-3})(4a^2+6a+9)\\\\
=\textcolor[rgb]{0,1,0}{2a}(4a^2+6a+9)\textcolor[rgb]{0,0,1}{-3}(4a^2+6a+9)\\\\
=[\textcolor[rgb]{0,1,0}{2a}(4a^2+6a+9)]+[\textcolor[rgb]{0,0,1}{-3}(4a^2+6a+9)]\\\\
=8a^3+12a^2+18a\;\;\;+\;\;\;-12a^2-18a-27\\\\
=8a^3+12a^2+18a\;\;\;\;\;\;\;-12a^2-18a-27\\\\$$

and you can finish it.  

sec=1/cos

first letter of normal one goes with 3rd letter of inverse  one. In this case that is C.

cos=a/h

so

sec=h/a