diff --git a/1sem/octave/07/07.zip b/1sem/octave/07/07.zip
new file mode 100644
index 0000000..a2c8d9d
Binary files /dev/null and b/1sem/octave/07/07.zip differ
diff --git a/1sem/octave/07/main.m b/1sem/octave/07/main.m
new file mode 100644
index 0000000..a3f4bdd
--- /dev/null
+++ b/1sem/octave/07/main.m
@@ -0,0 +1,17 @@
+#  33 - additive - 4
+len = 4;
+outf = fopen('results.txt', 'w');
+fprintf(outf, 'dk %d\n', len); 
+maxn = 2^(len - 1) - 1;
+
+for n = randi([-maxn maxn], 1, 100)
+  nstr = print_num_code(n, len);
+  nback = read_num_code(nstr);
+  fprintf(outf, '%d %s\n', n, nstr);
+  
+  if nback ~= n
+    error("`%d` not equal to `%d` (converted from `%s`)\n", n, nback, nstr);
+  end
+end
+
+fclose(outf);
diff --git a/1sem/octave/07/print_num_code.m b/1sem/octave/07/print_num_code.m
new file mode 100644
index 0000000..8c6b980
--- /dev/null
+++ b/1sem/octave/07/print_num_code.m
@@ -0,0 +1,3 @@
+function [s] =  print_num_code(n, len)
+  s = dec2bin(mod(n, 2^len), len);
+end
\ No newline at end of file
diff --git a/1sem/octave/07/read_num_code.m b/1sem/octave/07/read_num_code.m
new file mode 100644
index 0000000..11268be
--- /dev/null
+++ b/1sem/octave/07/read_num_code.m
@@ -0,0 +1,6 @@
+function [n] =  read_num_code(s)
+  n = bin2dec(s);
+  if s(1) == '1'
+    n -= 2^length(s);
+  end
+end
\ No newline at end of file
diff --git a/1sem/octave/07/results.txt b/1sem/octave/07/results.txt
new file mode 100644
index 0000000..86f0212
--- /dev/null
+++ b/1sem/octave/07/results.txt
@@ -0,0 +1,101 @@
+dk 4
+-7 1001
+7 0111
+-3 1101
+0 0000
+6 0110
+3 0011
+-2 1110
+-2 1110
+-7 1001
+-5 1011
+2 0010
+4 0100
+4 0100
+-4 1100
+-4 1100
+-4 1100
+0 0000
+6 0110
+-6 1010
+-3 1101
+2 0010
+-6 1010
+-1 1111
+-2 1110
+-2 1110
+-3 1101
+2 0010
+7 0111
+-6 1010
+0 0000
+2 0010
+2 0010
+-2 1110
+-6 1010
+4 0100
+-6 1010
+4 0100
+3 0011
+4 0100
+-3 1101
+-4 1100
+1 0001
+-3 1101
+3 0011
+-4 1100
+-1 1111
+6 0110
+1 0001
+1 0001
+7 0111
+2 0010
+3 0011
+-2 1110
+0 0000
+5 0101
+5 0101
+-4 1100
+-7 1001
+-4 1100
+0 0000
+2 0010
+-6 1010
+-6 1010
+-3 1101
+-5 1011
+4 0100
+-7 1001
+1 0001
+-6 1010
+-7 1001
+-5 1011
+5 0101
+-5 1011
+-6 1010
+-7 1001
+0 0000
+1 0001
+5 0101
+2 0010
+-3 1101
+2 0010
+-4 1100
+0 0000
+1 0001
+-7 1001
+0 0000
+0 0000
+7 0111
+5 0101
+3 0011
+-5 1011
+-4 1100
+0 0000
+-3 1101
+-1 1111
+-5 1011
+-1 1111
+-2 1110
+7 0111
+-6 1010