In Module 5, Topic A, students count two separate parts within teen numbers, 10 ones and some ones. They start by counting piles of 10 straws to understand 10 ones. In Lesson 2, students separate 10 ones and some ones from within teen quantities using an egg carton cut off to have 10 compartments. Continuing with decomposing, in Lesson 3, students circle 10 ones within teen quantities at the pictorial level. In Lessons 4 and 5, students count their 10 ones and some ones to 20 the Say Ten way (e.g., ten one, ten two, ten three, ten four, ten five, ten six, ten seven, ten eight, ten nine, 2 ten).
In Module 5, Topic B, students advance to a more abstract level, representing the decomposition of teen numbers first with Hide Zero cards (Place Value cards) and in Lesson 2 with number bonds. They then work from the abstract to the concrete and pictorial in Lessons 8 and 9 as they are directed to “show (and in Lesson 9 draw) me this many cubes (as teacher displays 13).” Application problems in Topic B are experiences with decomposition and composition of teen numbers (K.NBT.1) rather than word problems (1.OA.2). For example, in Lesson 6, the problem reads, “Gregory drew 10 smiley faces and 5 smiley faces. He put them together and had 15 smiley faces. Draw his 15 smiley faces as 10 smiley faces and 5 smiley faces.” In this instance, there is no unknown. We do not ask, “How many in all?” or “How many?” within a word problem setting. The students represent 15 with their Hide Zero cards both when the zero is hiding and when it is not hiding as they apply all their experiences from Topic A to deeply understand the meaning of the digit 1 in the tens place in teen numbers.
Module 5, Topic E’s Lesson 1 begins as students represent teen number decompositions and compositions by writing addition sentences. In Lesson 2, students make bonds with materials and hide one of the parts for their partner who must figure out what the hidden part is. The number bond with a hidden part is represented by the teacher as an addition equation with a missing addend, the hidden part (aligns to 1.OA.8). In Lesson 3, students compare teen numbers by counting and comparing the extra ones. For example, students decompose 12 into 10 and 2, and 16 into 10 and 6. They compare 2 ones and 6 ones to see that 16 is more than 12 using the structure of the 10 ones (MP.7). This is an application of the Kindergarten comparison standards (K.CC.6, K.CC.7), which move into the Grade 1 comparison standard (1.NBT.3). In Lesson 23, students reason about situations to determine if they are decomposing a teen number as 10 ones and some ones, or composing 10 ones and some ones to find a teen number. They analyze the number sentences that best represent each situation (K.NBT.1). Throughout the lesson, students draw the number of objects presented in the situation (K.CC.5).
