**Step 1:** Imagine you have some yummy cookies. 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 (15 cookies) Add ➕ **Step 2:** Now, imagine you get 6 more cookies. 🍪 🍪 🍪 🍪 🍪 🍪 (6 cookies) = **Step 3:** Put all the cookies together! 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 🍪 (21 cookies) Great! So, $15 + 6 = 21$ 🎉