This unit is designed to teach students how to add two 2 digit numbers where a grouping of 10 needs to be made in the ones place. This is not teaching the usual 2 digit addition with regrouping method. Instead, the children become very familiar with tens and ones and making groups of 10. This leads to a better understanding of the addition process.
6 how to add 2 digit numbers charts
10 count and record the tens and ones pages
10 how many tens and ones pages
10 circle groups of 10 and write the number shown pages
40 2 digit addition pages
Common Core State Standards:
1.NBT.1. Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
1.NBT.2. Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
* 10 can be thought of as a bundle of ten ones — called a “ten.”
* The numbers from 11 to 19 are composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.
* The numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or nine tens (and 0 ones).
1.NBT.4. Add within 100, including adding a two-digit number and a 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.