diff --git a/stdlib/arith.go b/stdlib/arith.go
new file mode 100644
index 0000000..36aeefc
--- /dev/null
+++ b/stdlib/arith.go
@@ -0,0 +1,182 @@
+/*   SHS: Syntactically Homogeneous Shell
+ *   Copyright (C) 2019  Aidan Hahn
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package stdlib
+
+import (
+    "fmt"
+    "strconv"
+    "git.callpipe.com/aidan/shs/ast"
+    "git.callpipe.com/aidan/shs/log"
+)
+
+// PKG WIDE TODO: BIGNUM SYSTEM
+// then write actually optimal routines once it is in place
+// perhaps we simply write out arithmetic routines that operate on the strings
+// then we need not worry about storage length.
+
+func add(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    var res float64
+
+    for i := in; i != nil; i = i.Next {
+        if i.Tag != ast.NUMBER {
+            log.Log(log.ERR, "Non-number given to ADD", "add")
+            return nil
+        }
+
+        token := i.Inner.(string)
+        isFloat := false
+        for _, char := range token {
+            if char == '.' {
+                isFloat = true
+                n, err := strconv.ParseFloat(token, 64)
+                if err != nil {
+                    log.Log(log.ERR, "Err parsing number: " + err.Error(), "add")
+                    return nil
+                }
+
+                res += n
+            }
+        }
+
+        if !isFloat {
+            n, err := strconv.ParseInt(token, 10, 64)
+            if err != nil {
+                log.Log(log.ERR, "Err parsing number: " + err.Error(), "add")
+                return nil
+            }
+
+            res += float64(n)
+        }
+    }
+
+    return &ast.Token{Tag: ast.NUMBER, Inner: fmt.Sprintf("%f", res)}
+}
+
+func sub(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    var res float64
+
+    for i := in; i != nil; i = i.Next {
+        if i.Tag != ast.NUMBER {
+            log.Log(log.ERR, "Non-number given to SUB", "sub")
+            return nil
+        }
+
+        token := i.Inner.(string)
+        isFloat := false
+        for _, char := range token {
+            if char == '.' {
+                isFloat = true
+                n, err := strconv.ParseFloat(token, 64)
+                if err != nil {
+                    log.Log(log.ERR, "Err parsing number: " + err.Error(), "sub")
+                    return nil
+                }
+
+                res -= n
+            }
+        }
+
+        if !isFloat {
+            n, err := strconv.ParseInt(token, 10, 64)
+            if err != nil {
+                log.Log(log.ERR, "Err parsing number: " + err.Error(), "sub")
+                return nil
+            }
+
+            res -= float64(n)
+        }
+    }
+
+    return &ast.Token{Tag: ast.NUMBER, Inner: fmt.Sprintf("%f", res)}
+}
+
+func mult(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    var res float64
+
+    for i := in; i != nil; i = i.Next {
+        if i.Tag != ast.NUMBER {
+            log.Log(log.ERR, "Non-number given to MULT", "mult")
+            return nil
+        }
+
+        token := i.Inner.(string)
+        isFloat := false
+        for _, char := range token {
+            if char == '.' {
+                isFloat = true
+                n, err := strconv.ParseFloat(token, 64)
+                if err != nil {
+                    log.Log(log.ERR, "Err parsing number: " + err.Error(), "mult")
+                    return nil
+                }
+
+                res *= n
+            }
+        }
+
+        if !isFloat {
+            n, err := strconv.ParseInt(token, 10, 64)
+            if err != nil {
+                log.Log(log.ERR, "Err parsing number: " + err.Error(), "mult")
+                return nil
+            }
+
+            res *= float64(n)
+        }
+    }
+
+    return &ast.Token{Tag: ast.NUMBER, Inner: fmt.Sprintf("%f", res)}
+}
+
+func div(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    var res float64
+
+    for i := in; i != nil; i = i.Next {
+        if i.Tag != ast.NUMBER {
+            log.Log(log.ERR, "Non-number given to DIV", "div")
+            return nil
+        }
+
+        token := i.Inner.(string)
+        isFloat := false
+        for _, char := range token {
+            if char == '.' {
+                isFloat = true
+                n, err := strconv.ParseFloat(token, 64)
+                if err != nil {
+                    log.Log(log.ERR, "Err parsing number: " + err.Error(), "div")
+                    return nil
+                }
+
+                res /= n
+            }
+        }
+
+        if !isFloat {
+            n, err := strconv.ParseInt(token, 10, 64)
+            if err != nil {
+                log.Log(log.ERR, "Err parsing number: " + err.Error(), "div")
+                return nil
+            }
+
+            res /= float64(n)
+        }
+    }
+
+    return &ast.Token{Tag: ast.NUMBER, Inner: fmt.Sprintf("%f", res)}
+}
diff --git a/stdlib/stdlib.go b/stdlib/stdlib.go
index 43d24fa..7c4dab6 100644
--- a/stdlib/stdlib.go
+++ b/stdlib/stdlib.go
@@ -37,6 +37,34 @@ func GenFuncTable() ast.FuncTable {
             TimesCalled:     0,
             Args:           -1,
         },
+
+        "+": &ast.Function{
+            Function:      add,
+            Name:        "add",
+            TimesCalled:     0,
+            Args:           -1,
+        },
+
+        "-": &ast.Function{
+            Function:      sub,
+            Name:        "sub",
+            TimesCalled:     0,
+            Args:           -1,
+        },
+
+        "*": &ast.Function{
+            Function:     mult,
+            Name:       "mult",
+            TimesCalled:     0,
+            Args:           -1,
+        },
+
+        "div": &ast.Function{
+            Function:      div,
+            Name:        "div",
+            TimesCalled:     0,
+            Args:           -1,
+        },
     }
 
     return stdlib