Sep 29, 2014

"One More" Math Fact Strategy

This year I started things off with a unit on math facts and I loved it!  Our strategies include: one (group) more, one (group) less, benchmark numbers, doubles, doubles plus one, and break apart (like breaking a 7 into a 5 and 2 to multiply).  A lot of the strategies fit with other concepts like multi-digit addition, subtraction, multiplication and even division.  We worked on strategies for solving math facts in place of memorization.  Only one third of kids can memorize easily, yet teachers often keep pounding on the same learning style hoping something will change with the child.  So below is one of the things I did differently this year. (Check out my Math Fact unit on tPt). Here's a part of a lesson showing the strategy of "one group more" or "one group less" using graph paper and arrays.

The Process:
(mathematical thinking questions included in the photos)

This activity also uses graph paper, but it shows the "doubling and halving" strategy for solving math facts.  For example, if the student knows the math fact 3x8 they can double it to find the product of 6x8, a much harder math fact to solve.

On graph paper, have your child draw and shade a 2x2 array (color two squares across and two squares down).  Ask them what shape was made (a square) and what the area is inside (4 squares); this is a tie-in to area and measurement.
On top of the 2x2 array, have your child draw and shade a 4x4 array.  Part of the larger array should overlap the smaller array.  If you want to, you can ask the questions shown in the picture.

On top of the 4x4 array, have your child draw and shade an 8x8 array.  Part of the larger array should overlap both the medium-sized and small arrays.  If you want to, ask the questions show in the picture.
Notice how well the student is able to communicate their mathematical thinking and how clearly they can relate their ideas.  Do they understand that doubling both numbers in the equation doubles both the length and the width of the shape, which actually quadruples the product?  Can they figure out a math fact equation that would be double 4x7?  Are they able to apply this strategy to other math facts?