When I spent my days as a classroom teacher, I would always cringe when my students would ask this question. If I said yes, they would be motivated to learn this information for a little bit of time so they could get the grade they wanted. If I said no, that was an invitation that they could tune me out for the rest of the lesson.
It's always such a relief that as homeschoolers, we don't give grades out. This means that if our kids don't understand something, we don't simply hand a failing grade out and move on to the next thing. No, we spend as much time as we need to so that our kids can understand and master the subject. They don't learn information to get an A to hang on the fridge, but so that they truly understand a concept which they can use to better their life in the real world.
Think about the time when your kids learned how to ride a bike. They didn't study theories and take tests on it and then were satisfied when they could pass with a B. No they practiced and practiced until they could ride without the aide of your hand propping them up. How should the rest of their education be any different?
When we take grades out of the picture we can leave false motivation for learning at the door. Our kids no longer have to worry about someone looking over their shoulder at the result of their studying. Instead they can be instrsically motivated to learn and master what it is that they are studying.
I challenge you to look at the curriculum you are currently using. Does it interest your child? Is it beneficial to their life? Are you just using it to check a box? Are you simply going through the motions of education? We have the freedom to tailor our kids' daily learning to one that inspires, motivates, and energizes them. If they ask you "When am I going to use this in real life?", you should have a solid answer.
Use this time of homeschooling to dive deep into their interests and watch it be a catalyst for attaining knowledge. Throw all grades out the window. Foster a love of learning and show them how they can practically apply it to their lives. When you take the pressure off to perform for grades, it leaves room to truly engage and master things that matter.