Ten Ones + More Ones
In this unit students • compose and decompose numbers 11–19 into ten ones and more ones, recording with an equation (e.g., 18 = 10 + 8); • write and identify numbers to 20.
Students in Kindergarten work with numbers 11–19 to lay a foundation for understanding place value in Grade 1, making with clear connections to addition and subtraction. They learn that the numbers 11–19 can be expressed as ten ones plus some more ones. They use objects and drawings to compose and decompose these numbers and match them to equations, e.g., 18 = 10 + 8, that parallel the visual models, such as ten-frames. This gives them additional practice with counting and writing numbers, as well as more time to work towards fluency with addition and subtraction within 5. These operations are part of the major work of grades K–2, so allowing students time to build a strong foundation with basic addition and subtraction concepts is crucial.
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