Topic 7 focuses on subtracting using Mental Math. Each lesson was introduced using interactive videos similar to the ones below. Click the box in the bottom, right corner of the video to maximize the video.
Interactive Math Story
Topic 7-2 Interactive Lesson
In Topic 7-2, we introduced two strategies to subtract numbers mentally by finding parts of 100. Some students struggled due to them wanting to add instead of subtracting. As time develops and their mathematic toolboxes grow, they will become better mathematicians.