diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index 32a73da..91a9828 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -34,7 +34,7 @@ jobs:
     - name: Build
       run: |
         cd ${{ matrix.build-dir }}
-        make -j6
+        make -j
     - name: Example
       run: |
         cd ${{ matrix.build-dir }}
diff --git a/README.md b/README.md
index 06d57e3..1008301 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
 numbers
 </h1>
 
+[![CMake CI Matrix](https://github.com/guuzaa/numbers/actions/workflows/cmake.yml/badge.svg?branch=main)](https://github.com/guuzaa/numbers/actions/workflows/cmake.yml)
+
 `numbers` is a library for C++17 and later versions that handles integer overflow similar to Rust. It simplifies integer computations and offers control over how to handle overflow situations.
 
 ## Features