diff --git a/packages/server/computation_container/math/math.cpp b/packages/server/computation_container/math/math.cpp
index acc7bcd3c..57256b824 100644
--- a/packages/server/computation_container/math/math.cpp
+++ b/packages/server/computation_container/math/math.cpp
@@ -5,137 +5,71 @@ namespace qmpc::Math
 {
 Share sum(const std::vector<Share> &v)
 {
-    Share ret;
-    for (const auto &a : v)
-    {
-        ret += a;
-    }
-    return ret;
+    Share e(FixedPoint(0));
+    return std::accumulate(v.begin(), v.end(), e);
 }
+
 Share smean(const std::vector<Share> &v)
 {
-    // Share avg(FixedPoint(0.0));
-    // for (int i = 0; i < size; i++)
-    // {
-    //     avg = avg + v[i];
-    // }
-    Share ret{};
-    for (auto a : v)
-    {
-        ret += a;
-    }
-    int size = std::size(v);
-    ret /= FixedPoint(size);
-
-    return ret;
+    assert(std::size(v));
+    return sum(v) / FixedPoint(std::size(v));
 }
 
-Share variance(std::vector<Share> &v)
+std::vector<Share> deviation(std::vector<Share> v)
 {
-    Share avg;
-
-    avg = smean(v);
-    std::vector<Share> var;
-    for (auto &a : v)
+    Share avg = smean(v);
+    for (auto &s : v)
     {
-        var.emplace_back(a - avg);
+        s -= avg;
     }
-    auto varVec = var * var;
-    Share ret{};
-    for (auto &a : varVec)
-    {
-        ret += a;
-    }
-    // FPのresolutionの制約により、FPだと1000より大きい数で割れないためdoubleで割っている
-    // double var_d = var.getDoubleVal();
-    int size = std::size(v);
-    ret /= FixedPoint(size);
+    return v;
+}
 
-    return ret;
+Share variance(const std::vector<Share> &v)
+{
+    auto dev = deviation(v);
+    auto var = dev * dev;
+    return smean(var);
 }
 
-FixedPoint stdev(std::vector<Share> &v)
+FixedPoint stdev(const std::vector<Share> &v)
 {
-    Share var;
-    var = variance(v);
+    Share var = variance(v);
+    FixedPoint var_val = open_and_recons(var);
 
-    FixedPoint stdev = open_and_recons(var);
-    auto value = stdev.getDoubleVal<qmpc::Utils::mp_float>();
+    auto value = var_val.getDoubleVal<qmpc::Utils::mp_float>();
     if (value < 0)
     {
         value = 0;
     }
-    auto r = sqrt(value);
-    FixedPoint ret{r};
-    return ret;
+    return FixedPoint(sqrt(value));
 }
-Share correl(std::vector<Share> &x, std::vector<Share> &y)
+
+Share covariance(const std::vector<Share> &x, const std::vector<Share> &y)
 {
-    int sizex = (int)x.size();
-    int sizey = (int)y.size();
+    auto devX = deviation(x);
+    auto devY = deviation(y);
+    auto devXY = devX * devY;
+    return smean(devXY);
+}
 
-    if (sizex != sizey)
+Share correl(const std::vector<Share> &x, const std::vector<Share> &y)
+{
+    if (x.size() != y.size())
     {
         qmpc::Log::throw_with_trace(std::runtime_error("input Size is not Equal"));
     }
-    Share aveX = smean(x);
-    Share aveY = smean(y);
 
     FixedPoint stdeX = stdev(x);
     FixedPoint stdeY = stdev(y);
 
+    // 0除算
     if (stdeX == FixedPoint(0) || stdeY == FixedPoint(0))
     {
         QMPC_LOG_ERROR("correl returns 0 when stdev is 0");
         return Share(FixedPoint(0));
     }
 
-    int n = sizex;
-    std::vector<Share> tmpX;
-    tmpX.reserve(n);
-    std::vector<Share> tmpY;
-    tmpY.reserve(n);
-    for (int i = 0; i < n; ++i)
-    {
-        tmpX.emplace_back(x[i] - aveX);
-        tmpY.emplace_back(y[i] - aveY);
-    }
-    auto tmpVec = tmpX * tmpY;
-    Share ret{};
-    for (auto &r : tmpVec)
-    {
-        ret += r;
-    }
-    ret /= stdeX;
-    ret /= stdeY;
-    ret /= FixedPoint(n);
-    return ret;
-}
-
-Share exp(const Share &x)
-{
-    // Nはマクローリン展開時の項数
-    // 1+x+x^2 ...  x^N-1
-    constexpr int N = 100;
-    auto *conf = Config::getInstance();
-    Share ret;
-    if (conf->sp_id == conf->party_id)
-    {
-        ret += 1;
-    }
-    std::vector<Share> px(N);
-    std::vector<FixedPoint> k(N);
-    px[0] = ret;
-    k[0] = 1;
-    for (int i = 1; i < N; ++i)
-    {
-        k[i] = k[i - 1] * i;
-        px[i] = px[i - 1] * x;
-    }
-    for (int i = 1; i < N; ++i)
-    {
-        px[i] /= k[i];
-    }
-    return std::accumulate(px.begin(), px.end(), Share{0});
+    return covariance(x, y) / (stdeX * stdeY);
 }
 }  // namespace qmpc::Math
\ No newline at end of file
diff --git a/packages/server/computation_container/math/math.hpp b/packages/server/computation_container/math/math.hpp
index d33b0da9c..4592fc048 100644
--- a/packages/server/computation_container/math/math.hpp
+++ b/packages/server/computation_container/math/math.hpp
@@ -1,8 +1,5 @@
 #pragma once
-#include <algorithm>
-#include <initializer_list>
-#include <iostream>
-#include <string>
+#include <numeric>
 #include <vector>
 
 #include "share/share.hpp"
@@ -12,13 +9,9 @@ namespace qmpc::Math
 using Share = qmpc::Share::Share<FixedPoint>;
 Share sum(const std::vector<Share> &v);
 Share smean(const std::vector<Share> &v);
-Share variance(std::vector<Share> &v);
-// 標準偏差
-FixedPoint stdev(std::vector<Share> &v);
-// 相関係数
-Share correl(std::vector<Share> &x, std::vector<Share> &y);
-Share exp(const Share &x);
-Share sigmoid(const Share &x, const FixedPoint &a = 1);
-Share open_sigmoid(const Share &x_s, const FixedPoint &a = 1);
-Share open_sigmoid_vector(const std::vector<Share> &v_s, const FixedPoint &a = 1);
+std::vector<Share> deviation(std::vector<Share> v);
+Share variance(const std::vector<Share> &v);
+FixedPoint stdev(const std::vector<Share> &v);
+Share covariance(const std::vector<Share> &x, const std::vector<Share> &y);
+Share correl(const std::vector<Share> &x, const std::vector<Share> &y);
 }  // namespace qmpc::Math
\ No newline at end of file
diff --git a/packages/server/computation_container/test/integration_test/math_test.hpp b/packages/server/computation_container/test/integration_test/math_test.hpp
index b60edf22e..7e4787591 100644
--- a/packages/server/computation_container/test/integration_test/math_test.hpp
+++ b/packages/server/computation_container/test/integration_test/math_test.hpp
@@ -163,7 +163,7 @@ TEST(MathTest, Correl)
 TEST(MathTest, Correl_0div)
 {
     std::vector<Share> x = {FixedPoint("2.0"), FixedPoint("2.0"), FixedPoint("2.0")};
-    std::vector<Share> y = {FixedPoint("10.0"), FixedPoint("10.0"), FixedPoint("10.0")};
+    std::vector<Share> y = {FixedPoint("9.0"), FixedPoint("10.0"), FixedPoint("11.0")};
 
     Share correl_rec = qmpc::Math::correl(x, y);
     FixedPoint target = open_and_recons(correl_rec);
@@ -225,30 +225,6 @@ TEST(MathTest, Correl_large)
     QMPC_LOG_INFO(correl_rec.getStrVal());
 }
 
-TEST(MathTest, ExpTest)
-{
-    Config *conf = Config::getInstance();
-    int n_parties = conf->n_parties;
-
-    // x = n_parties;
-    Share x{1};
-    auto start = std::chrono::system_clock::now();
-
-    auto exp_n = qmpc::Math::exp(x);
-    double expect = std::exp(n_parties);
-    auto exp_n_rec = open_and_recons(exp_n);
-    auto end = std::chrono::system_clock::now();
-    auto dur = end - start;
-
-    // 計算に要した時間をミリ秒（1/1000秒）に変換して表示
-    auto msec = std::chrono::duration_cast<std::chrono::milliseconds>(dur).count();
-
-    QMPC_LOG_INFO("share exp time is {}", msec);
-    QMPC_LOG_INFO("share exp_n is {}", exp_n_rec);
-    QMPC_LOG_INFO("expect exp_n is {}", expect);
-
-    EXPECT_NEAR(expect, exp_n_rec.getDoubleVal(), 0.001);
-}
 TEST(MathTest, correlVecExceptionTest)
 {
     constexpr int N = 28000;
diff --git a/scripts/libclient/src/tests/test_sum.py b/scripts/libclient/src/tests/test_sum.py
index c678d1088..ccf8f817d 100644
--- a/scripts/libclient/src/tests/test_sum.py
+++ b/scripts/libclient/src/tests/test_sum.py
@@ -22,9 +22,9 @@
          pd.DataFrame([2.0*10**18])),
 
         # small data case
-        (data_frame([[10**-8], [10**-8]], columns=["s1"]),
+        (data_frame([[10**-7], [10**-7]], columns=["s1"]),
          [1],
-         pd.DataFrame([2.0*10**-8])),
+         pd.DataFrame([2.0*10**-7])),
 
         # duplicated src case
         (data_frame([[1, 2, 3], [4, 5, 6]], columns=["s1", "s2", "s3"]),