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.
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:
