CONFIDENTIAL 1 Let's review what we learned in our last lesson. *We learned about doubling a number *We also learned about grouping numbers into groups of 10 to add easier *We talked about the different properties of addition: Commutative: order = Associative: grouping 25 + (15 + 2) =( ) + 2 Identity: zero = 45 ! Good Afternoon

CONFIDENTIAL 2 1.) Find the next number in the pattern. 22, 24, 26, 28, ____ 2.) Order these numbers from least to greatest ) = Let’s see what you remember

CONFIDENTIAL 3 Today we are going to learn about Subtraction. You might have heard these words to use subtraction: Take away, minus, fewer than, more than, or less. What is subtraction? Subtraction is when you take a smaller number from a larger number.

CONFIDENTIAL 4 When we subtract numbers we can either count back for smaller numbers

CONFIDENTIAL 5 Now for larger numbers we can count up Addition is always easier than subtraction Think: start at 6 and count up to 10, how many do you count up?

CONFIDENTIAL 6 Your turn to try some

CONFIDENTIAL 7 Addition and Subtraction are opposites of each other. Do you know what opposite means? Hot and cold are opposite words So are up and down. So if addition and subtraction are opposites, that means they each use fact families. Let’s do an addition problem to find the opposite subtraction problem 6 +8 = = 14 (Remember, these are also using the Commutative Property)

CONFIDENTIAL 8 1. If we know the addition problem, = 14 then… 2. We can find the subtraction problem = 6 or 14 – 6 = 8 Do you see how we used the Commutative Property again? These are called fact families. You use only 3 numbers.

CONFIDENTIAL 9 Subtraction When you subtract, you start with the larger number and then put the other 2 numbers: One will be the answer You can check subtraction by adding the 2 numbers together = 12

CONFIDENTIAL 10 You try a couple.. Make a subtraction sentence with each set of numbers

CONFIDENTIAL 11 You can also find the 3 rd number, by thinking what number added to this number = the answer? So 10 + ? = = 18

CONFIDENTIAL 12 Find the missing number =

CONFIDENTIAL 13 Break!

CONFIDENTIAL 14

CONFIDENTIAL 15 Regrouping to subtract 2 tens 4 ones - 8 ones You can’t take 8 ones from 4 ones so you have to regroup a set of 10’s 2 tens 4 ones 1 ten 14 ones

CONFIDENTIAL 16 1 ten 14 ones - 8 ones = 1 ten 6 ones -

CONFIDENTIAL 17 Your turn 7 tens 8 ones = ___ tens ___ ones

CONFIDENTIAL 18 Subtracting 1 digit from 2 digits with regrouping Sometimes this is also called borrowing. You are borrowing a group of 10 from the 10’s column 12 6

CONFIDENTIAL 19 Your Turn! = = =

CONFIDENTIAL 20 Assessment 1.) What are some words for subtraction? 2.)Which is easier for you: to count up or to count back? 3.) If you had this addition problem = 19 What would the subtraction problems be? 4)Could you answer this subtraction problem 25 – ? = ? = 25 and then what would the number be?

CONFIDENTIAL 21 5.)What is the answer ). Carol had 18 candies and ate 7. How many does she have left?

CONFIDENTIAL 22 Let’s review We learned the vocabulary words for subtraction We learned that you can count back or count up to subtract We learned that subtraction is the opposite of addition We learned about fact families: We found the missing number in subtraction problems: by thinking what number added to what number = the answer We learned how to regroup or borrow to subtract numbers

CONFIDENTIAL 23 You did a GREAT job today!