SOLUTION: Find the units digit of 7^157.
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Question 670006:  Find the units digit of 7^157. 
Answer by MathLover1(20850)   (Show Source): You can put this solution on YOUR website!
 To solve a question like this, one looks at  of powers and a  of . 
.................unit's dig. 
...............unit's dig. 
..............unit's dig. 
.............unit's dig. ...pattern:,,,
............
...........
...........
...........pattern is repeating
......
.....
.....
......pattern is repeating
So the unit's digits of powers of  follow a cycle of length : ,,, ... ... 
so let's find the remainder when we divide by : 
Since the remainder is , and  has the same unit's digit as , which is .
 
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