Addition and subtraction within 20 - Vocabulary

The fundamental concepts of addition and subtraction within 20 are introduced to Year 1 students through a variety of visual aids and mathematical symbols. Addition is represented by the '+' sign, which signifies the combination of two or more numbers to find the total, such as in the equation 3 + 2 = 5. Subtraction, often referred to as 'taking away', uses the '-' sign and involves removing one number from another, exemplified by 3 - 2 = 1. The '=' sign denotes equality, indicating that the values on either side of it are the same, such as in 6 = 3 + 3.

To aid understanding, several representations and models are used. A number line helps with counting on and back, while ten frames illustrate how numbers are made up of tens and units. The part-whole model visually breaks down a number into its constituent parts to show their sum as the whole, and the bar model similarly represents the whole and the sizes of its parts. Partitioning involves dividing numbers into smaller parts to simplify calculations. Students also learn about number sentences, related facts, and the principle of commutativity in addition, where the order of numbers does not affect the total. Strategies like 'counting on' and 'making 10' are taught to facilitate addition, especially when crossing the ten boundary, and number bonds are presented as pairs of numbers that add up to a given total. The vocabulary assessment for this topic covers all these key terms and concepts.