Return to Mathematics IndexA Method of Front-End Arithmetic

Eddie Newton Carver Area High School

l3l00 S. Doty Avenue

Chicago IL 60627

312-535-5250Objectives:

Grades 3-l2

Upon completion of the Front-End Mathematics lesson, students will be able

to:

a. Transfer computational fatigue from the most significant to the

least significant columns.

b. Eliminate carry-overs and their errors.

c. Use one or more of the fundamental laws of commutation, association and

distribution, and the concepts of place value and regrouping.Multicultural Aspects:

Many peoples contributed to the development of the modern system of

numerals. Any society that uses Arabic numerals can use the Front-End Method of

Arithmetic for calculating.Materials Needed:

Notebook Paper for a class of 20 students.

Pencils for the class.

Twenty store receipts from supermarkets.Strategy:

Students will be given four shopping lists and asked to estimate the

number of $20 bills needed to purchase the items on each list. Calculators are

not allowed.

Students will be asked to add the figures on the list to obtain the exact

totals.

Students will be taught the Front-End Method of Arithmetic.

Students will recalculate the shopping lists using front-end arithmetic

without calculators.

Example of front-end addition:

$37.55

63.86

97.23

8.98l8 25. 2.4.22l-7.62l0207.62 The numbers are lined up as usual in their proper vertical columns. The first column is totalled and the subtotal, 3+6+9=18, written in its proper place under the line. At this stage we already know that the final sum will exceed $l80. The second column is summed, its subtotal, 7+3+7+8=25, is written in its proper place under the line. The first two subtotals add up to $205, a second approximation to the final answer. The third column subtotal, 24, is again written in its proper place under the line. The first three subtotals give the partial sum $207.4, a third approximation to the final answer. The fourth column subtotal, 22, is again written in its proper place under the line. Added to the previous partial sum, it yields the final answer $207.62.Performance Assessment:

Students will be given a post-test consisting of ten front-end addition

problems using supermarket receipts. Students will be expected to use this new

method to compute the problems with l00% accuracy.Conclusions:

Front-end arithmetic provides an interesting variation for and supplement

to, the classical rear-end approach. Students are able to add columns of

figures without carrying. This method has real-world application to consumer

mathematics.Reference:

DeBethune, Andre J.A Method of Front-End Arithmetic, in Enrichment

for the Grades, The National Council of Teachers of Mathematics, Inc.

Washington, D.C., l963.