# What Do You Notice? poster – Crossed Lines

Here’s my latest *What Do You Notice?* poster. All you need is inch graph paper, a black sharpie, and small circular stickers (or two different colored sharpie pens to draw in the circles).

**Title: Crossed Lines**

**Skills**

K-2: colors, counting, even/odd numbers

3-5: multiplication, even/odd numbers, multiples of 3, square numbers

**Background Information**

Crossed lines is an easy strategy for learning multiplication facts. The horizontal and vertical lines represent the factors in the multiplication problem. For example, in the problem 4 x 3, students would draw 4 horizontal lines and then intersect them with 3 vertical lines as is shown in the last example above. The intersection of the lines is the answer to the problem. So for 4 x 3, there would be 12 intersections.

To make the strategy more visible, I used colored dots to highlight the intersections. I was deliberate in the colors I chose. The green dots represent an even product and the pink dots represent an odd product. Notice how all the products are multiples of 3. At a higher level, older students may notice that 3 x 3 makes a square and 9 is a square number.

Here’s what it looked like at the event: