Use of the Fraction Key on the Sharp EL 531X Calculator - YouTube
Amazon.com: Sharp EL-531TGBBW 12-Digit Scientific/Engineering Calculator with Protective Hard Cover, Battery and Solar Hybrid Powered LCD Display, Great for Students and Professionals, Black,Black and White : Office Products
Sharp Elsimate EL-531A 61 Function Scientific Calculator - Jack Berg Sales
Amazon.com: Sharp EL-531TGBBW 12-Digit Scientific/Engineering Calculator with Protective Hard Cover, Battery and Solar Hybrid Powered LCD Display, Great for Students and Professionals, Black,Black and White : Office Products