Best Answer

It is a 3.

Look at the ones digit of successive powers of 7; this need only be done by considering the multiplication of the ones digit of the previous power of 7 by 7 (as this is the only calculation that affects the ones digit as each successive power of 7 is the previous power multiplied by 7) and taking the result modulus 10 (to extract the new ones digit as any excess over 9 is carried into the tens column):

7¹ → 7 mod 10 = 7

7² → (7×7) mod 10 = 9

7³ → (9×7) mod 10 = 3

7⁴ → (3×7) mod 10 = 1

7⁵ → (1×7) mod 10 = 7

At this point the pattern of the ones digit will obviously repeat the sequence of the four digits {7, 9, 3, 1}.

To find the ones digit of any power of 7, take that power modulus 4 use that digit from the four digit sequence. Note that when taking the number modulus 4, the result will be in the range 0-3; when the result is 0, use the 4th digit from the sequence.

2015 mod 4 = 3

→ the third digit of {7, 9, 3, 1}, which is 3, will be the ones digit of 7²⁰¹⁵.

User Avatar

Wiki User

โˆ™ 2017-04-01 07:25:21
This answer is:
User Avatar
Study guides


20 cards

A polynomial of degree zero is a constant term

The grouping method of factoring can still be used when only some of the terms share a common factor A True B False

The sum or difference of p and q is the of the x-term in the trinomial

A number a power of a variable or a product of the two is a monomial while a polynomial is the of monomials

See all cards

J's study guide

1 card

What is the name of Steve on minecraft's name

See all cards

Steel Tip Darts Out Chart

96 cards





See all cards

Add your answer:

Earn +20 pts
Q: What is the one's digit of 7 to the 2015th power Explain the steps you took to reach your answer.?
Write your answer...
Related questions

How can you reach 911 by 4 digit?


Why is the light unable to reach the screen?

Explain why the light is unable to reach the screen

Using the digit 8 8 times and no other digit add numbers together to reach a sum of 1000?

888, 88, 8, 8, 8.

Explain how liquids reach a point where they boil?

They 'reach' it by heating up the liquid till boiling point is reached.

How Does Power Reach Us From Power Plant?

wires and transformers

A list of all three digit numbers?

Start at 100 and go on till you reach 999 then stop.

Explain how the nutrients in the digestive tract reach the body cells?

by diffusion

How do you use power of in a sentence?

The power of intention helps you to reach your goals.

How do you get a drivable pelican in halo reach?

to get a drivable pelican you must mod your console witch I will not explain and I am pretty sure there are no pelicans in Halo: Reach

What is your career aspiration in Human Resource?

You should help explain why you would be a good fit for the position. Explain your skills and how HR can help you reach your goals.

Explain what would happen if a gas would reach absolutes zero temperature?


What year did napoleon reach the height of his power?


How do you open door on dodge truck without slim Jim?

Coat hanger over the top edge and reach for a power lock button.Coat hanger over the top edge and reach for a power lock button.

Why mobile number is 10 digit?

It isn't - in UK it's 11 digits longbecause of huge number of subscribers.when the No. of subscribers will reach near 1 billion . one more digit will be added

How do you check power steering fluid on a 2002 Impala 3800 Series 2?

the power steering reservoir is normally located under the alternator so you would have to reach behind and then under it to reach the reservoir.

Explain how the structure of a sperm enables it to reach the ovum?

It has a long tail that helps it swim easily to reach the ovum, It has a pointed tip in the head of the sperm which allows it to effectively enter the ovum.

Which one of the following is not an octal number 29 75 16 102?

the highest digit used in octal is 7 so 29 ain't octal.

When will Naruto reach 5 tailed?

well it all depends really if he keeps on using that power he will reach 5 tails even more as stated by jiraiya that everytime he uses the power the seal weakens he doesn't reach five tails. He b;ows past it and goes to NINE.

Where is the power plant on Pokemon Crystal?

Its east of cerulean city use Surf on this route to reach the power plant.

Pokemon heartgold where is the part for the power plant?

When you reach cerulean city, misty will not be there, and all the power is out. You go to the power plat by surfing and follow the sequences there.

Why do netball players need power?

Netball players need power for when they're pasing the ball. If you don't have power and you throw the ball to someone it might not reach that person.

How do you reach Australia as a tourist from India?

calculate power gearbox output

During what period did egypt reach the height of its power?

new kingdom

How do you go super saiyan?

You have to reach a power level of over 9000!

During what year did Rome reach its height of power?

106 BCE