diff --git a/packages/base-formula/src/functions/math.ts b/packages/base-formula/src/functions/math.ts
index d0922435c..279d9c6ac 100644
--- a/packages/base-formula/src/functions/math.ts
+++ b/packages/base-formula/src/functions/math.ts
@@ -1,12 +1,19 @@
 // packages/base-formula/src/functions/math.ts
 import { register } from "./registry";
+import { makeErrorCell } from "../error";
 
 const num = (v: unknown): number | null => v == null ? null : Number(v);
 
 register({
-  name: "round", arity: { min: 1, max: 1 }, paramTypes: ["number"], returnType: "number",
-  eval: ([v]) => { const n = num(v); return n == null ? null : Math.round(n); },
-  doc: "Rounds to the nearest integer.", category: "math",
+  name: "round", arity: { min: 1, max: 2 }, paramTypes: ["number", "number"], returnType: "number",
+  eval: ([v, places]) => {
+    const n = num(v);
+    if (n == null) return null;
+    const p = places == null ? 0 : Math.trunc(Number(places));
+    const factor = Math.pow(10, p);
+    return Math.round(n * factor) / factor;
+  },
+  doc: "Rounds to the nearest integer, or to `places` decimals if given.", category: "math",
 });
 register({
   name: "floor", arity: { min: 1, max: 1 }, paramTypes: ["number"], returnType: "number",
@@ -44,8 +51,104 @@ register({
   eval: ([a, b]) => {
     const na = num(a), nb = num(b);
     if (na == null || nb == null) return null;
-    if (nb === 0) throw new Error("modulo by zero");
+    if (nb === 0) return makeErrorCell("DIV_BY_ZERO", "modulo by zero");
     return na % nb;
   },
   doc: "Remainder after division.", category: "math",
 });
+register({
+  name: "add", arity: { min: 2, max: 2 }, paramTypes: ["number", "number"], returnType: "number",
+  eval: ([a, b]) => {
+    const na = num(a), nb = num(b);
+    return na == null || nb == null ? null : na + nb;
+  },
+  doc: "Sum of two numbers.", category: "math",
+});
+register({
+  name: "subtract", arity: { min: 2, max: 2 }, paramTypes: ["number", "number"], returnType: "number",
+  eval: ([a, b]) => {
+    const na = num(a), nb = num(b);
+    return na == null || nb == null ? null : na - nb;
+  },
+  doc: "Difference of two numbers.", category: "math",
+});
+register({
+  name: "multiply", arity: { min: 2, max: 2 }, paramTypes: ["number", "number"], returnType: "number",
+  eval: ([a, b]) => {
+    const na = num(a), nb = num(b);
+    return na == null || nb == null ? null : na * nb;
+  },
+  doc: "Product of two numbers.", category: "math",
+});
+register({
+  name: "divide", arity: { min: 2, max: 2 }, paramTypes: ["number", "number"], returnType: "number",
+  eval: ([a, b]) => {
+    const na = num(a), nb = num(b);
+    if (na == null || nb == null) return null;
+    if (nb === 0) return makeErrorCell("DIV_BY_ZERO", "division by zero");
+    return na / nb;
+  },
+  doc: "Quotient of two numbers.", category: "math",
+});
+register({
+  name: "pow", arity: { min: 2, max: 2 }, paramTypes: ["number", "number"], returnType: "number",
+  eval: ([a, b]) => {
+    const na = num(a), nb = num(b);
+    return na == null || nb == null ? null : Math.pow(na, nb);
+  },
+  doc: "Base raised to an exponent.", category: "math",
+});
+register({
+  name: "sqrt", arity: { min: 1, max: 1 }, paramTypes: ["number"], returnType: "number",
+  eval: ([v]) => {
+    const n = num(v);
+    if (n == null) return null;
+    if (n < 0) return makeErrorCell("TYPE_MISMATCH", "sqrt of negative number");
+    return Math.sqrt(n);
+  },
+  doc: "Positive square root.", category: "math",
+});
+register({
+  name: "sum", arity: { min: 1, max: null }, paramTypes: "variadic-any", returnType: "number",
+  eval: (args) => {
+    // Null propagates as 0 so `sum(prop("A"), prop("B"))` still works when
+    // some cells are empty — matches Airtable/Notion semantics.
+    let total = 0;
+    for (const v of args) {
+      const n = num(v);
+      if (n != null && Number.isFinite(n)) total += n;
+    }
+    return total;
+  },
+  doc: "Sum of the arguments.", category: "math",
+});
+register({
+  name: "mean", arity: { min: 1, max: null }, paramTypes: "variadic-any", returnType: "number",
+  eval: (args) => {
+    const nums: number[] = [];
+    for (const v of args) {
+      const n = num(v);
+      if (n != null && Number.isFinite(n)) nums.push(n);
+    }
+    if (nums.length === 0) return null;
+    return nums.reduce((a, b) => a + b, 0) / nums.length;
+  },
+  doc: "Arithmetic average of the arguments.", category: "math",
+});
+register({
+  name: "median", arity: { min: 1, max: null }, paramTypes: "variadic-any", returnType: "number",
+  eval: (args) => {
+    const nums: number[] = [];
+    for (const v of args) {
+      const n = num(v);
+      if (n != null && Number.isFinite(n)) nums.push(n);
+    }
+    if (nums.length === 0) return null;
+    nums.sort((a, b) => a - b);
+    const mid = Math.floor(nums.length / 2);
+    return nums.length % 2 === 0
+      ? (nums[mid - 1] + nums[mid]) / 2
+      : nums[mid];
+  },
+  doc: "Middle value of the arguments.", category: "math",
+});