Watch this Teaching Channel video on counting within 100.

Note :

~ The teacher does not tell students that they are right or wrong after she asks “what comes next?”, rather she asks them to justify their answers and convince each other until they reach an agreement.

~ Teacher uses gestures and “turn and tell” to involve and engage all students in the work of the group

~ First grade students are essentially subtracting multi-digit numbers (100 – 75) even though they have never learned the standard algorithm for this. Students sorted “in a way that makes sense to them” and then used multiple strategies to figure out how many more were needed to get to 100.

~ Effort and perseverance are praised: “Good hard work!”