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Time sites. Kids Online Resources - KidsOLR, Time Tutorial, Early Childhood, Preschool. Practice Worksheets. Math Worksheet Creator - Greater Than, Less Than, Equal To. Free Printables. What’s Wrong with “Repeated Addition”? « Let's Play Math! [Photo by Alejandra Mavroski.]

What’s Wrong with “Repeated Addition”? « Let's Play Math!

Myrtle called it The article that launched a thousand posts…, and counting comments on this and several other blogs, that may not be too much of an exaggeration. Yet the discussion feels incomplete — I have not been able to put into words all that I want to say. Thus, at the risk of once again revealing my mathematical ignorance, I am going to try another response to Keith Devlin’s multiplication articles. Let me state up front that I speak as a teacher, not as a mathematician.

I am not qualified, nor do I intend, to argue about the implications of Peano’s Axioms. I will start with a few things we can all agree on… We All Agree on Some Things Elementary students will use addition to solve beginning multiplication problems. So What’s the Problem? So what is wrong with the definition, “Multiplication is repeated addition”? To define multiplication as repeated addition is to make multiplication a sub-species of addition.

And they are not the same. But… We need… Math Worksheet Creator - Basic Addition. Speed Arithmetic. Return to my Mathematics pagesGo to my home page © Copyright 1998, Jim Loy Addition of two numbers: Let's add these two numbers in our heads (i.e., without paper). Can you do that? Our first attempt is to do it like most of us do on paper: 6+7=3 carry the 1 (13), 1+6+2=9, 1+3=4, 2+9=11. Memory is why speed arithmetic experts (I call them "arithmetickers") usually add numbers like these from left to right. Let's try again: 2+9=11, 1+3=4, 6+2=8, 6+7=3 and that previous 8 should have been a 9 (because of the carry). Addition of columns: How about this addition problem? In the right column, a speed arithmetic person might group the 9 and the 1 (10), the two 5's (10), and then the 7+2+4 (13) to get 33.

Instead, what I do is add 29+37=66, then 66+15=81, then 81+21=102, 102+32=134, 134+85=219, and 219+44=263. Multiplication: 24 x48 ---- Speed arithmetic people multiply from left to right, too. 2x4 = 8 2x8 = 16 ---- 96 4x4 = 16 ---- 112 4x8 = 32 ---- 1152 See how that is done? Why? Addendum (tricks): Math Practice. Math Worksheets, Puzzles, Printables, Problems, Test Prep.

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Main Menu. S Math Worksheets. Free Multiplication Worksheets. Welcome to the multiplication facts worksheets page at!

Free Multiplication Worksheets

On this page, you will find Multiplication worksheets for practicing multiplication facts at various levels and in a variety of formats. This is our most popular page due to the wide variety of worksheets for multiplication available. Or it could be that learning multiplication facts and multiplication strategies are essential to many topics in mathematics beyond third grade math. We believe that learning the multiplication facts to the point of quick recall is a goal for all students. That's why we start you off with some multiplication tables, five minute frenzy charts and multiplication facts.

Free printable geometry worksheets. The worksheets below can be used as part of extra math homework.

Free printable geometry worksheets

These geometry worksheets are free and easily printable. They cover typical school work from 4th through 8th grade. They include questions on polygons, 3D objects, angles, and calculations of area, volume, coordinate geometry etc. The printable worksheets are listed below by subject area. Each listing includes a brief description of the questions included in the worksheets. Lines, Shapes , and Objects Lines and Line Segments e.g. Homeschool Math - free math worksheets, ebooks, lessons, curriculum guide. Free algebra worksheets.