1 U n t er r ich t splan Composing and Decomposing Numbers Altersgruppe: Grade 1 Texas - TEKS: G1.5.AR.B Hampton City Schools Math Power Standards: 1.1aSa, a, 1.1aSa' a', 1.1aSa' ', 1.1aSb, 1.1aSb', 1.1aSc, 1.1aSc ', 1.1aSd, 1.1aSd' Riverside USD Scope and Sequence: 1.N B T.1 [1.11] Oklahoma Academic Standards Mathematics: 1.N.1.4, 1.N.1.7 Virginia - Mathematics Standards of Learning (2009): 1.1a, 1.1b, K.4 a Fairfax County Public Schools Program of Studies: 1.1.a.1, 1.1.a.2, 1.1.b.1, 1.1.b.2, K.4.a.1 Mathematics Florida Standards (MAFS): 1.N B T.1.1 Alaska: 1.N B T.1 Minnesota: 1.1.1.1, 1.1.1.2 Nebraska Mathematics Standards: M A.1.1.1.a, M A.1.1.1.b, M A.1.1.1.c Indiana: 1.N S.1 Georgia Standards of Excellence: M GSE 1.N B T.1 Virginia - Mathematics Standards of Learning (2016): 1.1.a, 1.2.a Online-Ressourcen: J ars Away Opening Teacher present s Students pract ice Class discussion Math Pract ice Worksheet 5 1 5 1 0 1 5 5
2 M at h Obj ect ives E xpe ri e nc e multiple representations of two digit numbers P rac t i c e adding a multiple of 10 to another number Learn to compose and decompose 2 digit numbers De vel o p a deeper understanding of place value Ope ni ng 5 Write these 4 expressions on the board: 50 + 9 40 + 19 30 + 29 20 + 39 Ask students to share what they notice about these expressions. See if any students can add more equations that would fit with this set (such as 10 + 49, 59 + 0, 58 + 1, 41 +18, etc). T e ac he r prese nt s M at h game : J ars Away - Co unt - On up t o 60 15 Begin Jars A w a y - C o unt - On up t o 60 by figuring out how many balls are in the jars. For this episode, most of the jars will contain 10 balls but one of the jars will have less than 10 balls. In the above example, there are 39 balls in jars. Next, the episode will ask you to figure out how many balls are in the store altogether. You can click on the circle on the ball machine to have the balls fall out for easier counting. Sometimes there will be fewer than 10 balls in this machine and other times there will be more than 10 balls. There are a variety of ways to solve these problems and it can be very beneficial to
3 students to have a chance to share how they solved it and compare their strategy to that of their peers. Here are a few strategies you might see (based on the above example) and how you can write an equation to represent their thinking. A student might count on from 39 by ones until they have counted all the balls in the machine. An equation to represent this would be 39 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 = 51 A student might notice there are 39 in the jars and 12 in the machine. 39 + 12 = 51 Another student might think about moving one ball from the machine to the jar with 9. They would then have 4 full jars of 10 and 11 in the machine. 40 + 11 = 51 Another student might think about moving one ball from the machine to the jar with 9 and then putting 10 of the ones left in the machine into another jar. They would then have 5 jars and one in the machine. 50 + 1 = 51.
4 St ude nt s prac t i c e M at h game : J ars Away - Co unt - On up t o 60 10 Have the students play J ars Away - Co unt - On up t o 60 on their personal devices. Students who are ready for a challenge can record their total number of balls in each example along with several different equations that equal that number. Cl ass di sc ussi o n 15 Present this problem to your class. I have 52 balls that I want to arrange in the store. How many could go in jars and how many could go in the machine? Record responses and equations for each answer students give. There are a lot of possibilities! (Any equation in which the sum of two whole numbers is equal to 52 will work!) Here are a few you might hear. 50 in jars and 2 in the machine 50 + 2 = 52 40 in jars and 12 in the machine 40 + 12 = 52 49 in jars and 3 in the machine 49 + 3 = 52 33 in jars and 19 in the machine 33 + 19 = 52 Ask students to think about different ways we could decompose the number 95 into tens and ones. Use the jar and machine context if necessary. Record different equations the students come up with for 95.
5 M at h P rac t i c e : Co mpo si ng and De c o mpo si ng N umbe rs Wo rkshe e t 5 Give each student half a sheet of paper or ask them to record five different addition equations that equal the number 93. Have them share their equations with a partner or collect them to see which students still need more help and which students are ready to move onto more challenging problems.