Karen loved to talk on her phone. She chatted with her friends, played games, and watched videos. One day, her dad said, "Karen, our phone bill arrived today, and it's much higher than usual. It seems you've been using a lot of data." Karen was surprised and a little scared. Dad smiled kindly and said, "Let's sit down together and look at the bill. We can see which apps are using the most data and find ways to reduce it." So, Karen and her dad went through the bill carefully and checked the settings of her phone. They discovered that some apps were using data in the background. Dad showed Karen how to turn off background data for those apps and use Wi-Fi when available.