When my preschooler was just a bit younger, she confused the colors red and blue, black and white. I created a simple color sorting activity so she could practice with the colors at the same time to help clear up the confusion. (I wanted her to see blue next to red and black next to white.)
I used fabric scraps for the black-white activity and ribbon for the red-blue activity (leftover from a birthday present). Gather your colorful items, cut paper into small pieces or shapes. Place one curled up piece of masking tape (sticky side out) on the front of each box. Then stick on one item of each color or a piece of colored paper. (If using an item that will not stick to the tape, just place it in front of each box-like with Legos for example.)
Present the colored items mixed up in a pile and your toddler can sort them by placing the pieces in the designated boxes. It is important to use the color (or shape) words while your child completes this activity to help solidify the learning and make it multi-disciplinary.
Enjoy your time at home!