Learn the numbers 11-20 as a group of ten ones, and some more ones. Model numbers using arrays, near arrays and digits. Subitize with ten frames to name both parts, and answer "How many?" and "How many more make 20?"
Continue to encourage part-total thinking. Subitize both parts of a ten frame. How many are there and how many are missing – how many more are needed to make 10, the total. Subitize daily to build number sense, master the all-important combinations of 10, recognize shapes and solids, and learn geometric names. Prerequisites: K-67 ○ K-26
Model teen numbers as 10 and some more. 11 is 10 and 1. 12 is 10 and 2. The names for 11, 12, 13, and 15 can be confusing because they don't follow the pattern. Nicknames like "1 ten 1" for "eleven" and "1 ten 2" for "twelve" can help make sense of numbers and lay the foundation for place value. Practice writing by tracing. Prerequisites: K-62 ○ K-61, K-60, K-59
Use horizontal picture graphs to model teen numbers. Figure out how many in each category by counting all, counting on from 5, 10, or 15, adding smaller groups, comparing rows, and learning to read the graph's axis. Build number sense by quantifying, comparing, and using words like "more," "fewer," "greater," and "less." Prerequisites: K-63 ○ K-102
