Well, there are a few casual and friendly ways to express that you feel you’re not very intelligent in simple English. Here are a few examples:
- “I’m not the brightest crayon in the box.”
- “I’m not the sharpest tool in the shed.”
- “I’m afraid I’m not the brightest bulb in the room.”
- “I’m not the most brainy person you’ll ever meet.”
- “I’m not the smartest cookie in the jar.”
- “I’m not the most intelligent fish in the sea.”
- “I’m not the most academic person you’ll ever encounter.”
Remember, these expressions are often used in a light-hearted or self-deprecating manner and don’t necessarily reflect your actual intelligence.