Unit 10 Overview:

This unit is all about addition and subtraction! The children will solve addition and subtraction word problems within 20. They will learn how to solve subtraction word problems where they will need to compare two numbers to find the difference. The children will use the commutative property to add two addends in any order. They will solve problems with three addends and use the associative property to combine the three addends in different ways. They will find the unknown number in an addition and subtraction equation. The children will practice math facts within 20 and learn the strategy of making/breaking apart a 10 and using doubles/doubles plus 1 to help them add more fluently. Finally, the children will also ask and answer questions about the data in graphs and tally charts.

• Students will use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem. Explore real world addition and subtraction story structures (start unknown and comparison structures where "fewer" leads to adding and "more" leads to subtracting). (1.OA.A.1)
• Students will determine an unknown number within an addition/subtraction equation (regardless of position), being able to relate the three whole numbers. (1.OA.D.8).
• Students will add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., 8+6=8+2+4=10+4=14); decomposing a number leading to a ten (e.g., 13-4=13-3-1=10-1=9); using the relationship between addition and subtraction (e.g., knowing that 8+4=12, one knows 12-8=4); and creating equivalent but easier or known sums (e.g., adding 6+7 by creating the known equivalent 6+6+1=12+1=13).(1.OA.C.6)
• Students will understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true, and which are false? 6=6, 8=8-1, 5+5=2+5, 4+1=6-5 (1.OA.D.7)
• Students will add within 100, including adding a two-digit number and one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten. (1.NBT.C.4)
• Students will subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. (1.NBT.C.6)