Hi Everyone Welcome to class! July 28
Review 1 Single Digit Addition: 5 + 2 = ? Two Digit Addition:
Review 1 Continued Doubling: 7 + 7 = ? Halving:
Opposite Operations ● Double and half are opposite operations ● Addition and subtraction are opposite operations.
Review 2
Key Words: Addition - Plus - Total - Together - And
Key Words: Subtraction - More/Less - Need - Spent(e.g. money) - Difference - Left
Key Words: Half - Spli t/Share - Equally - Evenly - Half - 1/2
Key Words: Double - Double
Pictographs Graphs that have pictures instead of numbers They are easier to read We can easily find largest and smallest value To read a pictograph, we use skip counting
Method 1: Skip Counting With Chart 0 1 2 3 4 5 6 7 8 9 10 11 By 1 0 2 4 6 8 10 12 14 16 18 20 22 By 2 0 5 10 15 20 25 30 35 40 45 50 55 By 5 0 10 20 30 40 50 60 70 80 90 100 110 By 10
Key Words: Skip Counting - Each - Apiece
Method 2: Addition 2 + 2 + 2 + 2 = 8 5 + 5 + 5 = 15
This week, we will be moving away from top down addition/subtraction into left right addition/subtraction
Splitting 41 = 40 + 1 23 = 20 + 3 18 = 10 + 8
Two Digit Addition 41 + 22 = 40 + 1 + 20 + 2 = 63 57 + 32 = 50 + 7 + 30 + 2 = 89
Adding Tips When you add, always add the ONES and then the TENS. 41 + 22 = 63 You can recall the song.
Two Digit Subtraction 48 - 16 = 40 + 8 - 10 - 6 = 30 + 2 = 32 50 - 2 = 40 + 10 - 2 = 40 + 8 = 48
? + 6 = 9 OR 6 + ? = 9 ?
Reverse Operations
?
? = 9 - 6 = 3
Unknown Quantities 3 + ? = 9 <--> ? + 3 = 9 ? = 9 - 3 Fun Fact: This is because addition is commutative. 3 + 4 = 4 + 3 = 7
Well Known Result EVEN + EVEN = EVEN EVEN + ODD = ODD
Homework Your homework is the last 2 pages of today’s material as well as the puzzles. Also, please do the pictograph homework if you have not done so. If you are done those, you can do the extra word problems practice.
BONUS MATERIAL
Why? Think of an equation as a scale. Both sides of the scale must be equal. We can add or subtract the same number from both sides, and both sides must remain equal.
Subtraction This approach works for subtraction as well, although it is harder since there are two cases to consider.
Advanced: Doubling 23 + 23 = 20 + 20 + 3 + 3 = 46
Advanced: Halving 86 / 2 = 80 / 2 + 6 / 2 = 40 + 3 = 43 96 / 2 = 80 / 2 + 16 / 2 = 40 + 8 = 48
Extra Practice: Word Problems
Matt is 82 years old. Kevin is 53 years old. How much older is Matt than Kevin? In 15 years, how old will Matt be? What about Kevin? In 15 years, how much older is Matt than Kevin? 39 years ago, how old was Matt? What about Kevin? 39 years ago, how much older was Matt than Kevin?
T here are 26 eggs in the house today. Each day, the amount of eggs is one half of what they were yesterday. How many eggs were there one day ago? How many eggs will be there in one day? How many eggs were there two days ago? How many more eggs were there two days ago compared to today?
Fun Problems!
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