Solved 3,5,8

problem03.rb

@@ -0,0 +1,27 @@
+#Project Euler, Problem #3
+#What is the largest prime factor of the number 600851475143?
+
+def primeTest testnum
+  #"For each number between 2 and testnum-1, we will test if number%a = 0 and stop when it does"
+  (2..(testnum-1)).each {|a| return false if testnum % a==0}
+  return true
+end
+
+
+num = 600851475143
+#sumtest is the sum of the 2 prime factors, once we have both we can stop
+lastfactor = 1
+curr = 2
+sumtest = 1
+
+#while loop to test
+#every number must have 2 prime factors
+  while sumtest < num
+    if num % curr == 0 && primeTest(curr)
+      lastfactor = curr
+      sumtest*=curr
+    end
+    curr+=1
+  end
+# lastfactor will always have largest num last so we can just print it
+puts "num is #{lastfactor}"

problem05.rb

@@ -0,0 +1,22 @@
+#Project Euler, PROBLEM #5
+#2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
+#What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?
+
+def divisorTest testnum
+  #"We check if the input number is dividable by all numbers encased in 11-20"
+  (11..20).each { |x| return false if testnum % x != 0 }
+  return true
+end
+
+ceil = 20
+found = false
+
+while found == false
+  #tests if ceil works, if it does the loop will end and the console puts the number that works.
+  if divisorTest(ceil)
+    found=true
+    puts "#{ceil} is divisible by every number between 1 and 20."
+  end
+  #increments by 20 and starts with 20 inorder to save time, since checking every number would prove unoptimized
+  ceil+=20
+end

problem08.rb

@@ -0,0 +1,19 @@
+#Find the greatest product of five consecutive digits in the 1000-digit number. (used below)
+number = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450"
+#the number is in string format since a string is just an array of chars so its easy to use arrays
+
+loop = 0;
+hiscore = 0;
+currscore = 0;
+
+#length-4 to stop invalid memory to mess with things
+while loop < number.length-4
+  #to_i makes the character an integer
+    currscore = number[loop].to_i*number[loop+1].to_i*number[loop+2].to_i*number[loop+3].to_i*number[loop+4].to_i
+    if currscore > hiscore
+      hiscore = currscore
+    end
+    loop+=1
+end
+
+puts "highscore is #{hiscore}"