When you are teaching addition to your kid or first graders you have to do it in a playful way. You can pick any objects from your daily life it might be apple, orange, keys, coins or anything else.
Everyday objects can help you teach your child math addition easily. That objects don't have to be identical to be important in math. Counting apples is a great math lesson, but counting apples, oranges, and watermelons together expands her thought process.
Another way can be let your kid play some interesting math game to learn addition faster. I am a mother of 2.5 years old daughter. 🙂 My princess is learning her math with Number Bonds Memorizer App. Number Bonds Memorizer is an iPhone & iPad app that helps young kids memorize the number bonds (addition facts) through 10. She is learning quickly.
Hope you will find my answer helpful.