Here are our choices for curriculum in third grade: Third Grade Curriculum.
One explanation is in order. When I homeschooled my firstborn in third grade, we had pretty much the same curriculum, but for history we were in volume 3 of Story of the World. My youngest was in first grade and she was doing volume 3 alongside him.
I follow history, science, and other subjects we do together based on my oldest. We teach at his level and allow the youngest to pick up whatever she can for her age. She picks up a lot! If she has questions, we clarify some vocabulary or concepts without too much fuss.
When my youngest was in third grade, we were in volume 1, starting the 4-year cycle of Ancients, Medieval, Early Modern, and Modern all over again. My oldest was in fifth grade and, because we teach at his level, we started with volume 1 again.
One year, we did not finish our history curriculum during the school year. No problem. We finished it during the summer. Another year, we crammed two years of history into one. It works both ways.
It’s interesting to see how much they pick up and how much they retain. Every year, they mature and make new connections. Some names are familiar, but they do not remember why. That’s the beauty of teaching. You get to witness their process of discovering the world.