Before First Graders are able to solve mentally, they must develop a concrete understanding of 10 less or 10 more than a given two-digit number. This lesson provides my students an opportunity to transition to solving mentally.
The CCSS emphasizes that students should be able to mentally add and subtract 10, without having to count. Help students develop a conceptual understanding of repeatedly adding 10s in this lesson-this promotes mental math!
This task will offer a challenging activity and will also act as a piece of formative assessment as you look deeper into how well they can add or subtract ten from a number and plan your instruction from here.
The CCSS asks students to mentally find 10 more and 10 less, without having to count! This lesson helps students develop a conceptual understanding of +/- 10, which will give them the foundation they need to mentally calculate 10 more/10 less!