<p>look for patterns.</p>
<p>2^1 ends in 2
^2 4
^3 8
^4 6
^5 2
^6 4
…</p>
<p>see, it’s a 2 4 8 6 2 4 8 6…</p>
<p>pretty much it’s asking you what the 1’s place is in 2^400.</p>
<p>when our patter is 2 4 8 6, in which repeats itself once every 4 terms. Divide 400 by 4 and you dont get a remainder.</p>
<p>Meaning that you can repeat 2 4 8 6, 100 times, and you still end up at the END of the first term. Which is a 2 4 8 [6]. 6, Answer C.</p>
<p>-
Try this simpler version if you dont understand my justification</p>
<p>What is the remainder of 2^5 if it’s divided by 10?</p>
<p>Forget that we know it’s 32</p>
<p>Knowing it’s the 5th power, 5/4 mod 1 (this is another way to express remainder)</p>
<p>So we know that we repeat the 2 4 8 6 pattern once, and go over 1, in which gives up 2 4 8 6 [2]. And 32 does end in 2!</p>
<p>So when we get 400, which has no remainder. We basically go over 2 4 8 6 a hundred times and have no remainder, and we land on the last number, 6.</p>
<p>That’s much easier to explain with a piece of paper and my mouth.</p>
<p>Edit: I just read your stuff is from PR, which in my opinion is for chuckles. Some of the grammar problems I have done on there weren’t even English. I dont have a fond opinion of it.</p>