Math Is Fun Forum

Hi Bob,
Thanks for your help.
The 6 options inspired me.
I divided them into two groups:
One grade gets 3. For the other grades,each grade gets 1; one grade gets 1. For the other grades,each gets 2.
There are [(5!/2!)/3!]*2!*3=60 ways in the first group and [(5!/3!)/2!]*(3!/2!)*3=90 ways in the second group. So there are 150 ways in total.

We have a 12-hour time difference,so it is a new day for me but probably not for you. I'm sorry for that.

This joke reminds me of the game Minecraft for its sleep rule.

My outdated phone is unable to do that. Anyway,it's more helpful to sharpen my mind through thinking and exchanging solutions.

lna: the Napierian logarithm of a (also the natural logarithm of a)

I'm not good at english. I guess "touches the x axis" means it has only one intersection point with the x axis. Is that correct?
Do you know about vertical diameter theorem(the translator called this)? Draw a perpendicular line through the center of the circle to the intercept. The intercept is perpendicularly disseated by the line. Is that helpful?

Try "Luiz".

Oh,i see. I'm so sorry.

I don't have the symbols i needed in my outdated phone. So i trid hard to translate it into english. Can you understand?