SWAMPSCOTT – Marcy Yellin barely finished the final song in her performance Tuesday before her audience mobbed her hoping to get a hug from the singer-guitarist.”I’m her biggest fan,” said Nina Hamilton.Yellin is a music therapy teacher, not a rock star, and Hamilton is a Clarke School music therapy student who is learning basic skills by singing and clapping along with Yellin’s songs.Along with about a dozen other Clarke students, Hamilton has spent some of her school day afternoons learning by singing.”Music taps the brain like nothing else,” said Yellin.She said the rhythm underpinning music is a valuable tool for helping children with learning challenges grasp basic language and mathematical concepts. The Swampscott resident has performed music in schools for nine years, drawing on her background in education.Clarke special education teacher Melissa Caplan applied for and won grant money earlier in the school year to hire Yellin once a week. Clarke teachers work to help special education students learn alongside regular education children, so the music therapy classes include a mix of regular and special education students.”They have a variety of learning challenges and music stimulates the brain – it just makes them feel good,” Caplan said.Hamilton, Ayden Schmitt and other students swirled around with colorful scarves on Tuesday and followed Yellin’s directions to “touch your toes and turn around and touch your nose.” Schmitt picked his favorite color before the song started.”I like green because I like playing in the grass,” he said.Caplan obtained Clarke’s music therapy grant from Kate’s Voice, a Sudbury organization that focuses on teaching young students physical coordination and basic colors, letters and numbers into music.”Music therapy offers students with special needs opportunities to develop a wide range of skills in self expression, community and gross/fine motor areas,” states the Kate’s Voice website.Clarke Principal Jennifer Hunt said the music therapy class provides a good opportunity for students with learning challenges and classmates who do not need special help to have fun and help one another.”It’s calming,” she said.Yellin said music therapy is becoming more important in education at a time when spending cuts threaten to reduce or eliminate regular classroom or extracurricular arts programs.Hamilton and her classmates were sad to see Yellin leave Clarke on Tuesday.”Don’t worry, I’ll be back on Thursday,” she told them.