quick tricks

[qwerty123]

How would you guys estimate these more efficiently? --> [unparseable or potentially dangerous latex formula] yeah, i did 20*30*40. I know I did a lame approach, but I didn't want to multiply by 5's and stuff.
multiply by 143? I remember there was a fraction way or something...
[unparseable or potentially dangerous latex formula] - I found out that these are always either 1 or -1. Is this consistent with the real UIL tests or are they trying to trick me?...
I HATE it when they give those "evil", "happy".... numbers. I know what some of them are, but I was just wondering... Do anyone here actually do them? I personally skip.
Sum of roots taken three at a time?
also can someone give me bushel, rods, and acre conversions, too lazy to search #...

[101dalmatians]

[101dalmatians]

[101dalmatians]

[101dalmatians]

[darksaber21]

[101dalmatians]

[nsguy1350]

[unparseable or potentially dangerous latex formula] [unparseable or potentially dangerous latex formula]

[101dalmatians]

[qwerty123]

The sum of the roots taken 3 (three) at a time of
[unparseable or potentially dangerous latex formula]

ok, I know that [unparseable or potentially dangerous latex formula] is roots taken 2 at a time, but what about 3 or more at a time!!!

A question: To the people who gets to 70-80s...

How do you guys get so far!!! I can only make it to the 50-60s..
Is it mostly practice? Im pretty sure there are like too many tricks to remember...

[darksaber21]

[101dalmatians]

[qwerty123]

[101dalmatians]

[101dalmatians]

300th Topic Guys!!!!!! :P

[qwerty123]

Some more questions...

Easy approach to this?
[unparseable or potentially dangerous latex formula]
I missed it like 30 out of range!!
For these problems, I guess you just have to memorize the powers right to a good amount right?

[unparseable or potentially dangerous latex formula]
This one was brutal for me..

Anyway, I just want to see y'all thinking process for this...

[qwerty123]

Also, I remember there was a trick for like... [unparseable or potentially dangerous latex formula] and other variances of the 1234. What was it again?

[101dalmatians]

[101dalmatians]

[101dalmatians]

[101dalmatians]

The easy way to do the [unparseable or potentially dangerous latex formula] or [unparseable or potentially dangerous latex formula] problems is to round up and down to balance the approximation.
For example, I rounded up the [unparseable or potentially dangerous latex formula] and [unparseable or potentially dangerous latex formula]. So, I rounded down [unparseable or potentially dangerous latex formula] to [unparseable or potentially dangerous latex formula].
This stuff is hard. It only comes by practice...

[qwerty123]

thanks.
Is there a trick for the nth term of a fibonacci-type sequence, like:
The 11th term in the Fibonacci seq [unparseable or potentially dangerous latex formula] is

and trick for the sum of the 9th, 11th....

[darksaber21]

[darksaber21]

[101dalmatians]