diff --git a/notebooks/2a--NumPy.ipynb b/notebooks/2a--NumPy.ipynb
index b5ebb9d7804299e1854219c0b2c56ee4c9c78340..f28c3c05102d919a7d707a62ba4da006989f3cb6 100644
--- a/notebooks/2a--NumPy.ipynb
+++ b/notebooks/2a--NumPy.ipynb
@@ -1144,10 +1144,11 @@
     "det = linalg.det(A)             # determinant\n",
     "P = linalg.pinv(A)              # pseudoinverse (accepts rectangular matrices)\n",
     "\n",
-    "# Further sparse matrices creation\n",
+    "# Further sparse matrix operations\n",
     "A = sparse.random(N, N, density=0.01, format='csr')\n",
     "B = sparse.random(N, N, density=0.01, format='csr')\n",
-    "C, D = sparse.diags(np.arange(4), 1), sparse.kron(B, A)\n",
+    "C = sparse.diags(np.arange(4), 1)\n",
+    "D = sparse.kron(B, A)               # kronecker product of matrices\n",
     "ev, evec = splinalg.eigs(A, 2)      # 2 largest eigenvalues\n",
     "u, s, vh = sparse.linalg.svds(A, 2) # 2 largest singular values"
    ]