Sorting is an easy concept to model for infants and toddlers.
Place five green grapes and four red grades mixed in front of your baby. Then say, "I will get the green grapes and place it on this side." Get the green grapes and place all of them on the right side. Then say, "Now the red grapes are on the left." Then say, "The green grapes are now all in one group." Point to it. And follow it with, "This is the group of red grapes." You can use this as an opportunity to model the concept of more and less by saying, "The green grapes are more than the red grapes."
You can use red and green apples to illustrate sorting concept. Or you can mix fruits and vegetables also or a mix of toys. Lego or Mega blocks or wooden cubes are good models to use to illustrate math concepts.
The concept of proportion can be modeled using plastic cubes or blocks.
Place two cubes on top of each other on one side. Then get four plastic cubes with the same color and size. Place it on top of each other on the other side of the table. They should be about 10 inches from each other. Point to the four cubes and say, "This is two times taller" than "The two blocks," pointing to the two cubes. Vary it by using three cubes on one side and six cubes on the other side.
Make Math relevant your to child's life. The concepts of Math when introduced as part of daily life with fun can make our children learn Math without sweat. They will even excel if you follow these recommendations.