diff --git a/code3/notry.py b/code3/notry.py
new file mode 100644
index 000000000..6258a8603
--- /dev/null
+++ b/code3/notry.py
@@ -0,0 +1,6 @@
+astr = 'Hello Bob'
+istr = int(astr)
+print('First', istr)
+astr = '123'
+istr = int(astr)
+print('Second', istr)
diff --git a/code3/tryexcept.py b/code3/tryexcept.py
new file mode 100644
index 000000000..b8a6e6fd7
--- /dev/null
+++ b/code3/tryexcept.py
@@ -0,0 +1,16 @@
+astr = 'Hello Bob'
+try:
+    istr = int(astr)
+except:
+    istr = -1
+
+print('First', istr)
+
+astr = '123'
+try:
+    istr = int(astr)
+except:
+    istr = -1
+
+print('Second', istr)
+
diff --git a/code3/trynum.py b/code3/trynum.py
new file mode 100644
index 000000000..bf7ba0580
--- /dev/null
+++ b/code3/trynum.py
@@ -0,0 +1,11 @@
+rawstr = input('Enter a number:')
+try: 
+    ival = int(rawstr)
+except: 
+    ival = -1
+
+if ival > 0 :  
+    print('Nice work')
+else:  
+    print('Not a number')
+
diff --git a/lectures3/Pythonlearn-01-Intro.pptx b/lectures3/Pythonlearn-01-Intro.pptx
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diff --git a/lectures3/Pythonlearn-02-Expressions.pptx b/lectures3/Pythonlearn-02-Expressions.pptx
index 0371833fb..6c8c758c7 100644
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diff --git a/lectures3/Pythonlearn-03-Conditional.pptx b/lectures3/Pythonlearn-03-Conditional.pptx
index 3e9e53e99..9fdfe2c4b 100644
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