remove exercise numbering

Author: rlanzafame

book/flow/Exercises/01.ipynb

@@ -56,7 +56,7 @@
     }
    },
    "source": [
-    "## Exercise 2.2.1\n",
+    "## Exercise\n",
     "\n",
     "One of the most crucial applications of <code>if</code> statements is filtering the data from errors and checking whether an error is within a certain limit.\n",
     "\n",
@@ -166,7 +166,7 @@
     }
    },
    "source": [
-    "## (Searching) Exercise 2.2.4\n",
+    "## (Searching) Exercise\n",
     "\n",
     "Conditional expression is a way how one can compress an <code>if</code> statement to a more compact (and logical) statement. Your task is to rewrite the below <code>if</code> statement by using the <i>'conditional expression'</i> technique."
    ]
@@ -289,7 +289,7 @@
     }
    },
    "source": [
-    "## Exercise 2.4.3\n",
+    "## Exercise\n",
     "\n",
     "Here you need to write a function that is able to sort any list consisting only of real numbers, in the descending order. For example, the list $[19, 5, 144, 6]$ becomes $[144, 19, 6, 5]$. However there are three possible options to complete correctly the code where the dots `...` are placed.\n",
     "\n",
@@ -332,7 +332,7 @@
     }
    },
    "source": [
-    "## Exercise 2.4.5\n",
+    "## Exercise\n",
     "\n",
     "In this exercise you will perform <a href=\"https://en.wikipedia.org/wiki/Downsampling_(signal_processing)\">downsampling</a> of a provided 'regular' 2D list. Downsampling is a procedure where only a subset of the data is sampled (to reduce its size, for example). Below a visual aid of what downsampling of a 2D list is. Instead of using all the data available, your task is to downsample the 2D list to keep only the data of every $a$-th row and every $b$-th column, including the first element $(a_{0,0})$.<br><br>$$A = \\left[\\begin{array}{ccccc}\n",
     "a_{0,0} & \\dots & a_{0,b} & \\dots & a_{0,2b} & \\dots & \\dots & a_{0,nb}\t& \\dots\\\\\n",