diff --git a/cli/exercise_01/a.pl b/cli/exercise_01/a.pl
new file mode 100644
index 0000000..e9761ae
--- /dev/null
+++ b/cli/exercise_01/a.pl
@@ -0,0 +1,10 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+
+print "Hello world\n";
+
+
+1;
+__END__
diff --git a/cli/exercise_01/b.pl b/cli/exercise_01/b.pl
new file mode 100644
index 0000000..99c9503
--- /dev/null
+++ b/cli/exercise_01/b.pl
@@ -0,0 +1,30 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+
+my $num = 4000 / 7;
+print "$num\n";
+
+print int($num + 0.005) . "\n";
+
+printf("%.3f\n", $num);
+
+printf("00%.3f\n", $num);
+
+
+sub show_signed {
+    my ($num) = @_;
+    if ($num gt 0) {
+        printf("+%.3f\n", $num);
+    } else {
+        printf("%.3f\n", $num);
+    }
+}
+
+show_signed($num);
+show_signed($num - 1000);
+
+
+1;
+__END__
diff --git a/cli/exercise_01/c.pl b/cli/exercise_01/c.pl
new file mode 100644
index 0000000..52cbd37
--- /dev/null
+++ b/cli/exercise_01/c.pl
@@ -0,0 +1,32 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use Math::Complex;
+
+
+sub quad {
+    my ($a, $b, $c) = @_;
+    my $positive = (
+        ($b * -1) - sqrt(($b ** 2) - (4 * ($a * $c))) / (2 * $a)
+    );
+    my $negative = (
+        ($b * -1) + sqrt(($b ** 2) - (4 * ($a * $c))) / (2 * $a)
+    );
+
+    return ($positive, $negative);
+}
+
+
+my @xx0 = quad(1, 2, 3);
+printf("%s, %s\n", $xx0[0], $xx0[1]);
+
+my @xx1 = quad(4, 5, 6);
+printf("%s, %s\n", $xx1[0], $xx1[1]);
+
+my @xx2 = quad(7, 8, 9);
+printf("%s, %s\n", $xx2[0], $xx2[1]);
+
+
+1;
+__END__
diff --git a/cli/exercise_01/d.pl b/cli/exercise_01/d.pl
new file mode 100644
index 0000000..0462989
--- /dev/null
+++ b/cli/exercise_01/d.pl
@@ -0,0 +1,40 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use Math::Complex;
+
+
+print "Entrez-vous\n";
+
+my ($a, $b, $c) = (rand(100), rand(100), rand(100));
+
+print "\$a=$a\n";
+print "\$b=$b\n";
+print "\$c=$c\n";
+
+
+sub quad {
+    my ($a, $b, $c) = @_;
+    my $positive = (
+        ($b * -1) - sqrt(($b ** 2) - (4 * ($a * $c))) / (2 * $a)
+    );
+    my $negative = (
+        ($b * -1) + sqrt(($b ** 2) - (4 * ($a * $c))) / (2 * $a)
+    );
+
+    return ($positive, $negative);
+}
+
+
+my @result = quad($a, $b, $c);
+printf("%s, %s\n", $result[0], $result[1]);
+
+
+1;
+__END__
+
+
+
+1;
+__END__