diff --git a/modules/04_arrays_and_strings/src/multidimensional.cpp b/modules/04_arrays_and_strings/src/multidimensional.cpp
index 83a6c79..195954f 100644
--- a/modules/04_arrays_and_strings/src/multidimensional.cpp
+++ b/modules/04_arrays_and_strings/src/multidimensional.cpp
@@ -1,9 +1,32 @@
 #include "multidimensional.hpp"
 
+#include <algorithm>
+#include <numeric>
+
 namespace arrays {
 
-auto create_matrix(int rows, int cols, int fill) -> Matrix { (void)rows; (void)cols; (void)fill; return {}; }
-auto transpose(const Matrix& matrix) -> Matrix { (void)matrix; return {}; }
-auto row_sums(const Matrix& matrix) -> std::vector<int> { (void)matrix; return {}; }
+auto create_matrix(const int rows, const int cols, const int fill) -> Matrix {
+    return Matrix(rows, std::vector(cols, fill));
+}
+
+auto transpose(const Matrix& matrix) -> Matrix {
+    auto new_mat = Matrix(matrix[0].size(), std::vector(matrix.size(), 0));
+    for (size_t row = 0; row < matrix.size(); ++row) {
+        for (size_t col = 0; col < matrix[row].size(); ++col) {
+            new_mat[col][row] = matrix[row][col];
+        }
+    }
+    return new_mat;
+}
+
+auto row_sums(const Matrix& matrix) -> std::vector<int> {
+    auto sums = std::vector(matrix.size(), 0);
+    auto idx = 0;
+    for (auto row: matrix) {
+        sums[idx] = std::ranges::fold_left(row, 0, std::plus{});
+        idx++;
+    }
+    return sums;
+}
 
 }  // namespace arrays