Why give students the definitions? Why not give them enough information so that they can create the definitions on their own? The Common Core state Standards in Mathematics along with the National Council of Teachers of Mathematics Standards emphasize allowing students to be actively involved in creating their learning. Through this, they will learn to:

-reason abstractly and quantitatively
-construct viable arguments and critique the reasoning of others
-attend to precision
-look for and make use of structure

Besides, the reason I like to teach this way is that it’s waaaay more fun and the learning is deeper. It’s a win/win.

CCSS: K.G.2; K.G.4; 1.G.1; 2.G.1; 3.G.1; 4.G.2