1. M

    Basic Digit Problems

    Question: What is the product of 23 and 79 to one place of accuracy? 1600 or 2000. Seeking help. Thanks. Regards, Mushfique
  2. sakonpure6

    Digit Arrangement

    Hello! This is what I have done: a) We can choose from 6 numbers for the first digit ( we exclude 0), 6 digits for the second (we exclude the first but include 0) and finally 5 digits for the third (we exclude the first and second). So total number of possibilities = 6 *6 *5 = 180 ways b) I...
  3. M

    Unit's digit problem

    Hello Find the units digit of 7^7^7^7.... Please provide some hints. Thanks
  4. M

    Find unit's digit

    Hello Find unit's digit of 7^11^13^17 Solution : evaluate 11^13^17 = 2431 cyclicity of 7 is 4 2431%4=3 So unit's digit of 7^2431 is same as unit's digit of 7^3 = 3 Is there any method to solve this problem without evaluating 7^11^13^17? Thanks
  5. J

    Sum of even digit f the number

    Let P(n) denote the sum of the even digits of the number "n"\;, foe example: P(8592) = 8+2 = 10\;, Then value of \displaystyle \sum_{r=1}^{100}P(r) =
  6. W

    Significant digit? how to work this out?

    Hi. I would like to ask those that have done a bit on computational Maths. I thought I understood it but my lecture notes gives another example and i don't get it: It reads: actual value = 23.496 and estimate = 23.494 The the error is |actual - estimate|= 0.002. The actual value has four...
  7. I

    How many 4 digit numbers

    How many 4 digit numbers between 3,000 and 7,999 contain at least one 2? How do I set this up?
  8. N

    Leading digit in decimal notation

    Hello! I have this problem: How many of the numbers 2^m, for 0<=m<=M, have leading digit 1 in decimal notation?
  9. A

    Which are the digits that never appear in any units' digit of any square number?

    He's a maths problem I am stuck with... Thanks for your help in advance. List the digits that will not be in the units' digit of any square number? (please show clear reasoning)
  10. aldrincabrera

    Can Math Guess the Next 3 Digit Combination?

    Hey there, just curious, if we have a game (say, lottery) and the game lets us choose a 3 digit combination from numbers 1 to 9 (repeating), can we somehow predict the next three digit combination?? I have seen a formula for this but i doubt its effectiveness. Just wondering.
  11. K

    probability of repeating digit

    Hi! What is the probabilty that in a 10-digit number, digit 7 repeats 6 times (no more or less, exactly)? or in other words, what is the probability that in a random 10-digit number there will be 6 sevens. thanks
  12. I

    13th and 20th digit

    find 13th and 20th digit of 13202013
  13. R

    8 digit number

    Find a 8 digit number which starts with 1984 and is divisible by 6,7,8,9.Step by step explanation will be appreciated.
  14. C

    Find the 2013th digit after the decimal point in the expression of...

    Let m=\frac{\sqrt{10^{4024}-1}}{3} Find the 2013th digit after the decimal point in the expression of \sqrt{m} It seems a similar problem. xkcd &bull; View topic - math problem - driving me crazy But I don't think so. I can't write m to (\sqrt{a}+\sqrt{b})^n a,b,n is integer numbers
  15. T

    Number of sequences of 8 digits where no digit occurs exactly 3 times?

    Consider the problem of counting the number of sequences of 8 digits where no digit occurs exactly 3 times. (a) Solve this problem by the method of inclusion and exclusion. (b) Solve this same problem by the method of exponential generating functions. I am having trouble getting started...
  16. W

    What is the units digit of the following number (sum of powers)

    Hello. I'm having problems solving this problem. What is the units digit of the following number: (1- \sqrt{3} )^{2000} + (1+ \sqrt{3} ) ^{2000} I wouldn't have any problems solving this, were it not for the square root of 3. Please, help.
  17. W

    probability of correctly guessing 1,2,3 or 4 digits out of 4 digit number

    I have two questions and it's a little more complicated than the title implies. I just spent almost 2 hours reviewing basic probability and reading lottery-related websites and I just don't have time to keep going with this on my own (I'm making a game and it's nothing to do with lotteries...
  18. K

    Unit digit

    What is the unit digit of the expansion (44)^4,(55)^5,(88)^8.. I want the deep explanation... Please..(Crying)
  19. N

    Four digit integer, unable to solve, confusing

    A positive four digit integer abcd has the following properties a>b>c>d a=b+c b=c-d If M is highest possible value for abcd What is the value of M?