Using 5x: What is it?

 This multiplication strategy allows students to use their knowledge of 10x tables to relate to the 5x facts.

Overview

Once students have a good understanding of the ten times tables, they move to the five times table to help students see relationships between the products. For example, 5 is half of 10, so if you want to know what 5 x 6 is you could multiply 6 by 10 and then halve the product to get 30.

Supporting Students Using 5x

Students who have experience counting by fives and identifying the five fact patterns on a hundreds chart usually do not have difficulty learning the five facts. A wide variety of songs, poems, and storybooks based on fives are available that will support learning this strategy. Educators will often notice students using their fingers to skip count by 5's when thinking about their 5 times facts. This is an easy way for students to think, however skip counting is additive thinking. As numbers become larger, additive thinking is no longer enough and students need to shift to multiplicative thinking. For example, when considering 42x5, it is not efficient to skip count by 5's, 42 times. 

Using open arrays to model 10x facts and halving the arrays can be good practice for students to see the connection. The use of intentional array images can also help students to make sense of this concept in a visual way. Educators can also plan their number strings around this idea to slowly build on the relationship between 10x and 5x. 

                     Consider this; 

10x10

10x5

2x10

12 x 10

12 x 5

Example of Array images:

                             First focus on 10x Intentionally connect to 5x being                         half of 10x

Where to Next?

Once students are confident using the 10x and 5x relationships, they can be encouraged to extend into Partial Products.