As a former substitute teacher for Pre-K to 5th grade music classes, I always liked having age-appropriate sing-along songs handy, that students loved singing. Here are some of my favorites for 1st & 2nd grade classes (they do better with more challenging song, and they can remember more, so songs that build upon previous verses are fun):
Inchworm Teaches skip counting, multiplication of twos, or standard measuring. This song is more complex as the class sings one part while the teacher sings another part.
On Top of Spaghetti (a hit from 1st – 5th grade)
Slimey to the Moon is a Sesame Street skit which features a special song by Tony Bennett.
It’s Not Easy Being Green originally sung by Kermit the Frog.
Sing is a song by Joe Raposo, which is sung in this video clip by A-List celebrities from the year 2000.
I Don’t Want to Live on the Moon is sung by Ernie from Sesame Street.
Monster in the Mirror is sung by Grover from Sesame Street.
Head, Shoulders, Knees, & Toes