diff --git a/unit08_blockchain/lab/src/ether01.sol b/unit08_blockchain/lab/src/ether01.sol
index 8b13789..a474025 100644
--- a/unit08_blockchain/lab/src/ether01.sol
+++ b/unit08_blockchain/lab/src/ether01.sol
@@ -1 +1,33 @@
+pragma solidity ^0.8.0;
 
+contract mymath {
+
+function sqrt(uint x) public view returns (uint y) {
+    uint z = (x + 1) / 2;
+    y = x;
+    while (z < y) {
+        y = z;
+        z = (x / z + z) / 2;
+    }
+}
+function sqr(uint a) public view returns (uint) {
+    uint c = a * a;
+    return c;
+  }
+
+function mul(uint a, uint b) public view returns (uint) {
+    uint c = a * b;
+    return c;
+  }
+
+  function sub(uint a, uint b) public view returns (uint) {
+    return a - b;
+  }
+
+  function add(uint a, uint b) public view returns (uint) {
+    uint c = a + b;
+    return c;
+  }
+
+
+}