Solve first task

Exercises/exercise-1/Code/A_BasicsTodo.hs

@@ -87,20 +87,23 @@ floatSevenByThree = 7 / 3
     Check your solutions with the REPL.
 
 
-x :: Integer
-x = 2 ^ 3
+>>> x :: Integer = 2 ^ 3
 
-y :: Float
-y = 2.0 ^ 3
+>>> y :: Float = 2.0 ^ 3
 
-a :: ?
-a = x + 5
+>>> a :: Integer = x + 5
 
-b :: ?
-b = y/2
+b :: Float
+>>> b = y/2
+>>> :t b
+b :: Float
 
-c :: ?
-c = y `div` 3
+c :: Error
+>>> c = y `div` 3
+>>> :t c
+No instance for (Integral Float) arising from a use of `div'
+In the expression: y `div` 3
+In an equation for `c': c = y `div` 3
 
 -}
 
@@ -179,7 +182,7 @@ aListOfInts = [ 1, 2, 3 ]
 {- Exercise
     Fill out the type, check your solutions with the REPL.
 
-    friendGroups :: ?
+    friendGroups :: [[String]]
     friendGroups =
       [ ["Peter", "Anna", "Roman", "Laura"]
       , ["Anna","Reto"]
@@ -215,11 +218,15 @@ lessThanPairs = [ (x,y)
     all square numbers between 1 and 100.
 -}
 squares :: [Integer]
-squares = error "fixme"
+squares = [ x^2 | x <- [1..(floor (sqrt 100))]]
+-- >>> squares
+-- [1,4,9,16,25,36,49,64,81,100]
 
 {- Exercise
     Use list comprehension to declare a list that contains
     all  odd square numbers between 1 and 100.
 -}
 oddSquares :: [Integer]
-oddSquares = error "fixme"
+oddSquares = [ x^2 | x <- [1..(floor (sqrt 100))], odd (x^2)]
+-- >>> oddSquares
+-- [1,9,25,49,81]