Week 8: Multiplication Strategies

We've been working on multiplication strategies to help children get better at doing multiplication mentally. Some children found these strategies challenging but we'll continue to practice. These strategies are meant to help speed up the math work but ultimately, students must choose a strategy that helps them arrive at the right answer. Here is a breakdown of the strategies we've tried:

Multiplication Strategies for Faster Mental Math

Partial Products Method

Using the expanded form of the factors and the distributive property, we break down the factors into a set of easier to solve questions. The product of these parts are then added together to get a final product.

Ex)  345 X 8 =

      (300+ 40+ 5) X 8=

      (300 X 8) + (40 X 8) + (5 X 8) =

       2400 + 320 + 40 = 2760

Associative Property

When given three or more factors, group together factors that result in products that are friendlier numbers.

Ex)  5 X 18 X 2 = (5 X 2) X 18= 10 X 18 = 180

Subtraction Property

A factor is changed into a friendlier number through rounding up.  This factor is renamed into a number expression using subtraction. Using the distributive property, multiply the parts of the number sentence then subtract the partial products to get the final answer.

Ex)  48 X 7 =

      (50 – 2) X 7=

      (50 x 7) – (2 X 7) =

       350 – 14 = 336

Addition Property

A factor is changed into a friendlier number through rounding down.  This factor is renamed into a number expression using addition. Using the distributive property, multiply the parts of the number sentence then subtract the partial products to get the final answer. This is very similar to the partial product method. 

Ex)  48 X 7 =

      (40 + 8) X 7=

      (40 x 7) + (8 X 7) =

       280 + 56 = 336

Halving and Doubling

A factor is split in half so that it creates an easier to solve fact. Double the partial product to get the final product.

Ex) 16 X 25 =

     (8+ 8) X 25=

     (8 X 25) + (8 X 25) = 200 + 200 = 400 

Here's what is happening next week:

• We are meeting our Caring School Communities Buddies on Monday! We are partnering with Ms. Varriale's and Ms. Luo class 2-203. We'll also have buddies PE with them on Wednesday.
• We are starting our writing units on Personal and Persuasive Essays. Students have reviewed the five paragraph essay structure and we've used the boxes and bullets outline format to plan our essays. This year, we will focus on making out thesis more universal and using transition words to communicate our points more effectively. 
• We have also begun our study of the Native Americans of New York. We will focus our studies on the Iroquois and Algonquian tribes. 

Finally, my thanks go out to the parents who came to Old Stone House with us. Mrs. Knowles, Mr. Marquez, Mrs. Hudgins, Mrs. Dekel, Ms. Tyler ,and Mr. Soans were awesome facilitators. They really helped make the trip a successful learning experience! I will publish some pictures in an upcoming post. 

Have a great weekend!