How big of a knife can a ten year old have?

The size of a knife a ten-year-old can have varies by location due to differing laws and regulations. Generally, it's advisable for children to use small, child-friendly knives designed for safety, such as those used for cooking or outdoor activities. Supervision is crucial to ensure safe handling and usage. Ultimately, parents should assess their child's maturity and skills before allowing them to use any knife.