Unit 8 Overview:

In this unit, children will use their understandings of place value to add a two-digit number and a one-digit number. They will also add a two-digit number to a multiple of ten. The children will learn that they need to add tens to tens and ones to ones and sometimes, they will need to make a ten. The children will learn how to subtract a multiple of ten from a two-digit number and that when they do, the tens place will decrease by the number of tens they are subtracting but the ones place will stay the same. The children will show their addition and subtraction solving strategies using pictures, drawings and models and will be expected to explain their work.

• 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 be able to subtract multiples of 10, within the range of 10-90, from multiples of 10 in the range of 10-90 using concrete manipulatives, drawings, and/or strategies based on place value. (1.NBT.C.6)