Addition and subtraction within 20 - Add by counting on - Presentation

In a series of fluency and reasoning teaching slides focused on addition and subtraction within 20, the concept of 'Add by Counting On' is introduced to young learners. This method of addition is a fundamental skill where instead of counting all items from the beginning, students learn to start with the larger number and count forward. For example, if a child has 8 counters and wants to add 3 more, they are encouraged to hold the number 8 in their mind and count on three more steps – 9, 10, 11 – to reach the total of 11. This technique simplifies the process of addition and helps develop mental arithmetic skills.

Students practice this skill through various activities. They are presented with simple addition problems, such as 5 + 3, and are guided to count on from the first number to find the sum. For instance, starting from 5 and counting on three steps – 6, 7, 8 – leads to the answer of 8. The lesson also includes comparing the efficiency of counting on in different orders, such as whether counting on from 5 or from 3 is more efficient when solving 5 + 3. Further activities involve using visual aids like dominoes and dice to reinforce the counting on method. For independent work, students are tasked with continuing to count on from a given number and writing down the numbers they say, as well as identifying numbers that are not part of the sequence.