Division on the Cranmer Abacus Sara Larkin Math Consultant Iowa Educational Services for the Blind and Visually Impaired Resource used: Millaway, S. M. (2002). Abacus basic competency: A counting method. American Printing House for the Blind.

Prerequisites The student must know the multiplication tables The student should be aware of terms used in division such as dividend, divisor, quotient, and remainder

Abacus Skills The student must be able to set numbers on the abacus The student must be able to read numbers on the abacus The student must be able to demonstrate an understanding and proficiency in the use of the Rules for subtraction on the abacus

Setting Up Division The entire abacus is used In 92 ÷ 4 = 23, the dividend is 92, the divisor is 4, and the quotient is 23. In other words, the dividend ÷ divisor = quotient The dividend is set on the extreme right The divisor is set on the extreme left The quotient will end up between the two with any remainder left all the way to the right There will be an empty rod between the quotient and the remainder

Dividing Check to see if the divisor will go into the first digit of the dividend If it does, move the right index finger from that digit over two digits to the left and place the answer If it doesn’t go into the first digit, move the right index finger over to the next digit right. Use the two digits as a two digit number to see how many times the divisor goes into that two digit number. Move that right index finger sitting on the 2 nd digit over two digits to the left and place the answer Multiply the answer with the divisor and subtract from the dividend Repeat this process until no more division can be done

Practice Dividing Group A 69 ÷ 3 = ÷ 4 = ÷ 2 = 41 Group B 95 ÷ 5 = ÷ 8 = ÷ 2 = 734

More Practice Group C 315 ÷ 7 = ÷ 6 = ÷ 5 = 415 Group D 58 ÷ 3 = 19 r ÷ 7 = 62 r ÷ 8 = 741 r 6