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Chalk To Write On The School Blackboard It Is Also Known As Gypsum And Chalk Or Pastel It Is A White Clay That Prepared In Bars Is Used To Write On The
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Chalk To Write On The School Blackboard It Is Also Known As Gypsum And Chalk Or Pastel It Is A White Clay That Prepared In Bars Is Used To Write On The
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Chalk To Write On The School Blackboard It Is Also Known As Gypsum And Chalk Or Pastel It Is A White Clay That Prepared In Bars Is Used To Write On The
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Chalk To Write On The School Blackboard It Is Also Known As Gypsum And Chalk Or Pastel It Is A White Clay That Prepared In Bars Is Used To Write On The
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