I, my husband, and my mom must be missing something. I'm struggling to understand the way long division is taught with quotient checking. I understand estimating the divisor and divident as tens as this is how I naturally learned division. I think I understand the process, but am having difficulty in understanding HOW the child is to ocme up with the lightly writte "trial" divisor. Does one take the quotient and find the EXACT divisor it'd be without having a remainder? Use a calculator? Later on, in Lesson 124 (on page 245) the lightly written numbers do not match up exactly. (42 x 8 = 336 and 36 x 5 = 180 and 41 x 7 = 287) I apologize for not "getting it;" I am sure there must be a simple explanation.

Rachel

Jun 27, 2011 - 3:53PM

Re: Level E, Lessons 122 and Beyond

Hi, Lori. My name is Rachel with RightStart and yours is a great question! I contacted Dr. Cotter to get her perspective - answer:-) - for your question. Here is what she wrote:

'First I must apologize to discover there are errors on page 245.

For the first problem on page 245, the thought process goes like this: To find the trial quotient, divide 29 by 4 [ 7 ]. Next to check if 7 will work, divide 290 by 7 [ 41 ] Yes, it works. (Had it been less than 41, we would have had to try 6 as a trial quotient.) So multiply and subtract.

To find the next trial divisor, divide 33 by 4 [ 8 ]. [ 41 ] Yes, it works. Again, multiply and subtract.

It is not necessary to write the division results shown grayed, but it might be helpful for awhile.

I hope this helps.

Joan Cotter'

I also wanted to forward to you the 'corrections' link. When users send in a correction, RightStart changes the manuals/worksheets so they are printed correctly from that point on. In addition, they list the corrections on the website. Feel free to check it at any time. Here is the link: http://www.alabacus.com/pageView.cfm?pageID=304.

If you have further questions, please do not hesitate to email info@alabacus.com or call our help line at (888) 272-3291.