diff --git a/src/Makefile.test.include b/src/Makefile.test.include
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -58,6 +58,7 @@
   test/mempool_tests.cpp \
   test/merkle_tests.cpp \
   test/miner_tests.cpp \
+  test/monolith_opcodes_type.cpp \
   test/multisig_tests.cpp \
   test/net_tests.cpp \
   test/netbase_tests.cpp \
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -304,10 +304,10 @@
                 return true;
 
             case OP_BIN2NUM:
-                return true;
+                return false;
 
             case OP_NUM2BIN:
-                return true;
+                return false;
 
             case OP_AND:
                 return true;
@@ -945,6 +945,22 @@
                                 bn = bn1 - bn2;
                                 break;
 
+                            case OP_DIV:
+                                if (!fEnabledOpCodesMonolith) {
+                                    // Disabled opcode.
+                                    return set_error(
+                                        serror, SCRIPT_ERR_DISABLED_OPCODE);
+                                }
+                                break;
+
+                            case OP_MOD:
+                                if (!fEnabledOpCodesMonolith) {
+                                    // Disabled opcode.
+                                    return set_error(
+                                        serror, SCRIPT_ERR_DISABLED_OPCODE);
+                                }
+                                break;
+
                             case OP_BOOLAND:
                                 bn = (bn1 != bnZero && bn2 != bnZero);
                                 break;
@@ -1238,6 +1254,73 @@
                         }
                     } break;
 
+                    //
+                    // Conversion operations
+                    //
+                    case OP_BIN2NUM: {
+                        // (in -- out)
+                        if (stack.size() < 1) {
+                            return set_error(
+                                serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
+                        }
+                        valtype bin = stacktop(-1);
+                        // big endian to little endian conversion
+                        std::reverse(bin.begin(), bin.end());
+                        CScriptNum num(bin, false);
+                        if (num > (INT_MAX >> 1) || num < (INT_MIN >> 1)) {
+                            return set_error(
+                                serror, SCRIPT_ERR_INVALID_BIN2NUM_OPERATION);
+                        }
+                        stack.pop_back();
+                        stack.push_back(num.getvch());
+                    } break;
+
+                    case OP_NUM2BIN: {
+                        // (in size -- out)
+                        if (stack.size() < 2) {
+                            return set_error(
+                                serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
+                        }
+                        CScriptNum num(stacktop(-2), fRequireMinimal);
+                        int64_t size =
+                            CScriptNum(stacktop(-1), fRequireMinimal).getint();
+                        if (size < 1 ||
+                            static_cast<uint64_t>(size) >
+                                CScriptNum::nDefaultMaxNumSize) {
+                            return set_error(
+                                serror, SCRIPT_ERR_INVALID_NUM2BIN_OPERATION);
+                        }
+                        // Produces a byte vector of num and check if input size
+                        // is valid
+                        valtype vchNum = num.getvch();
+                        if (size < vchNum.size()) {
+                            return set_error(
+                                serror, SCRIPT_ERR_INVALID_NUM2BIN_OPERATION);
+                        }
+                        // Initialize byte vector for result
+                        valtype result;
+                        result.reserve(size);
+                        bool neg{false};
+                        // Avoid negative zero
+                        if (!vchNum.empty()) {
+                            neg = *vchNum.rbegin() & 0x80;
+                            *vchNum.rbegin() &= ~0x80;
+                        }
+                        // Pad result to declared input size
+                        size_t pad = size - vchNum.size();
+                        for (uint8_t i = 0; i < pad; ++i) {
+                            result.push_back(0);
+                        }
+                        for (auto i = vchNum.rbegin(); i != vchNum.rend();
+                             ++i) {
+                            result.push_back(*i);
+                        }
+                        if (neg) *result.begin() |= 0x80;
+                        stack.pop_back();
+                        stack.pop_back();
+                        stack.push_back(result);
+                    } break;
+
                     default:
                         return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
                 }
diff --git a/src/script/script_error.h b/src/script/script_error.h
--- a/src/script/script_error.h
+++ b/src/script/script_error.h
@@ -20,6 +20,10 @@
     SCRIPT_ERR_SIG_COUNT,
     SCRIPT_ERR_PUBKEY_COUNT,
 
+    /* Operands checks */
+    SCRIPT_ERR_INVALID_BIN2NUM_OPERATION,
+    SCRIPT_ERR_INVALID_NUM2BIN_OPERATION,
+
     /* Failed verify operations */
     SCRIPT_ERR_VERIFY,
     SCRIPT_ERR_EQUALVERIFY,
diff --git a/src/script/script_error.cpp b/src/script/script_error.cpp
--- a/src/script/script_error.cpp
+++ b/src/script/script_error.cpp
@@ -34,6 +34,10 @@
             return "Signature count negative or greater than pubkey count";
         case SCRIPT_ERR_PUBKEY_COUNT:
             return "Pubkey count negative or limit exceeded";
+        case SCRIPT_ERR_INVALID_BIN2NUM_OPERATION:
+            return "Invalid OP_BIN2NUM operation (check operand values)";
+        case SCRIPT_ERR_INVALID_NUM2BIN_OPERATION:
+            return "Invalid OP_NUM2BIN operation (check operand values)";
         case SCRIPT_ERR_BAD_OPCODE:
             return "Opcode missing or not understood";
         case SCRIPT_ERR_DISABLED_OPCODE:
diff --git a/src/test/CMakeLists.txt b/src/test/CMakeLists.txt
--- a/src/test/CMakeLists.txt
+++ b/src/test/CMakeLists.txt
@@ -35,6 +35,7 @@
 	mempool_tests.cpp
 	merkle_tests.cpp
 	miner_tests.cpp
+	monolith_opcodes_type.cpp
 	multisig_tests.cpp
 	net_tests.cpp
 	netbase_tests.cpp
diff --git a/src/test/monolith_opcodes_type.cpp b/src/test/monolith_opcodes_type.cpp
new file mode 100644