unit digit of 793^3361+432^531+944^77
Answers
Step-by-step explanation:
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Given:
A number in exponential form 793^3361+432^531+944^77.
To Find:
The units digit of the given expression.
Solution:
1. The given number is 793^3361+432^531+944^77.
2. The number can be also written as,
=> (790+3)^3361+(430+2)^531+(940+4)^77,
=> Any number whose units digit is 0 has a value of 0 for any positive power of that number. For example, 100^7483 has a units digit of 0.
3. The units digit of 3^n is,
- 3 for 4n + 1 values,
- 9 for 4n + 2 values,
- 7 for 4n + 3 values,
- 1 for 4n values.
4. The units digit of 2^n is,
- 2 for 4n + 1 values,
- 4 for 4n + 2 values,
- 8 for 4n + 3 values,
- 6 for 4n values.
5. The units digit of 4^n is,
- 4 if the value of n is odd,
- 6 if the value of n is even.
6. 3361 can be written as 4(840) + 1, hence the units digit of 3^ 3361 is 3.
7. 531 can be written as 4(132) + 3, hence the units digit of 2^531 is 8.
8. 77 is an odd value, hence 4^77 has the units digit 4.
9. Hence, the units digit of the given expression is,
=> 3 + 8 + 4 = 15,
=> Units digit = 5.
Therefore, the units digit of the expression 793^3361+432^531+944^77 is 5.