Elementary Mathematics

Week 9

Building Subtraction and Multiplication Problems

Building Subtraction

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Building Multiplication

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Show Subtraction and Multiplication Problems

Showing Subtraction

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To start these problems off, I start by putting the amount of symbols that the first number shows. If the number is a negative then I use the subtraction sign and if the number is positive, I use the addition sign.Then I add zeros as necessary to make sure that I am able to take away what it is asking me to take away. Sometimes the problem will have you take away from a number that is bigger, so in those cases (like the first problem below) you won't have to add any zeros.5 - 2 = 3 (5 positive take away 3 positive)+ + + + + -3 - (-2) = -1 (3 negative take away 2 negative)- - - -3 - 6 = -9 (3 negative take away 6 positive)- - - - - - - - -+ + + + + + -2 + 7 = 5 (2 negative plus 7 positive)- - + + + + + + +

Showing Multiplication

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For these problems, you also have to add zeros if necessary in order to get the correct answer. You can add as many zeros as you want as long as it is enough. For the first and last problem below, I did not have to add any zeros, I just had to put the correct number in the correct number of groups.3(-3) = -9 (3 groups of 3 negative)- - - - - -- - --5(2) = -10 (Take away 5 groups of 2 positive) + + + + + + + + + +- - - - - - - - - --2(-4) = 8 (Take away 2 groups of 4 negative)+ + + + + + + + - - - - - - - - 2(3) = 6 (2 groups of 3 positive)+ + + + + +

Integers

Solving Subtraction

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Adding the oppositeKeep change-change - short way to add the oppositeExamples: K C C34 - (-52) ---> 34 + (+52) = 34 + 52 = 86K C C -45 - 12 --->. -45 + (-12) = -57For this problem, we could use Hector's diagram as well and see that 45 would have 2 - signs over it and the 12 would have only 1. Upon determining that, we could see that we are going to add them together and the solution would be a negative number.K C C25 - 60 ---> 25 + (-60) = -35This problem is a lot like the last one, all you have to do is see that one sign is the same and one is different so we are going to subtract them and because the sign on the bigger one leave a negative, the answer will then be negative.

Multiplication/Division Rules

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-3(-6) - A negative TIMES a negative = a positive2(-4) - A positive TIMES a negative = a negative7(5) - A positive TIMES a positive = a positive Examples: 75---- = 15 Same sign (both numbers are positive), so it is a positive 5-3(5) = -15 Different sign (one is positive and one is negative), so it is negative-17(-24) = 408 Same sign, so it is a positive

Week 10

Intro to Fractions

Understanding Fractions

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When is 6 bigger than 10?NEGATIVE there is no context... 6 whats?6 trains and 10 bikes (This is context and it helps students be able to identify when 6 is bigger than 10)Is 25 big or small?Again, this needs context.25 marbles or 25 basketballs (The context helps the students to visualize what they are going to answer)Given 5 We know that we have 5 of somethingHow big are these 5 things though?Numerator vs. DenominatorNumerator ---> number of things we have---------------Denominator ---> the total possibleORNumerator ---> number of things we have----------------Denominator ---> the size of the piecesPractice:?--- ----> The size of the pieces are different10 (big or twice)?--- 20 (small or half) The size of the pieces is inversely related to the size of the denominator4 (more)--- ----> How many of each size piece we have?7 (less)--- ?

Solving Fractions

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This topic is super hard to type out, so I linked a video that has 7 tricks on how to solve different fractions.

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Comparing Fractions

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Determining which fraction is bigger using <, >, or = and our reason behind it...7/13 > 11/23 - Reason: Anchor fractions 1/22/9 < 2/7 - Reason: same number of pieces/size of each piece14/15 > 9/10 - Reason: missing one small piece4/12 < 5/12 - Reason: more of the same size piece13/16 < 25/28 - Reason: missing three small pieces4 9/10 < 5 1/3 - Reason: comparing whole numbers7/16 > 3/8 - Reason: multiply to make the same size pieces

Week 7

Alternative Algorithm: Subtraction

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Expanded Form425+314=? = 739400+20+5300+10+4-----------------700+30+9 = 739Equal Addends: Add equal amount to each numbers (can be any number as long as it is equal).42-35=? = 7 42 + 5 = 47 - 35 + 5 = 40------------------- 7

Multiplication

Intro to Multiplication

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Timed Test: Ineffective because of the stress they put on our young studentsProgress Chart: Chart that shows the students what score they got--->Students will be able to see their scores and if they are falling below, they will start to dread the timed test which is what makes them ineffective.--->Instead we should use a progress chart to show students how they are improving that way it will motivate and encourage them instead of shame them.Flash Cards: Increases automaticity and is highly encouraged(should make your own flashcards)Tricks (9s): Not great to teach because it is only a one number strategy

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Alternative Algorithms

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Expanded Form:Left to Right: Lattice:

Division

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Long Division:This is a harder way to divide that most schools teach their students.Long division requires students to remember a whole series of steps that can get confusing and they are more susceptible to making mistakes.

Repeated Subtraction

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Repeated Subtraction: This method is great for students who are learning division because it allows them to subtract whatever number instead of having to know their multiplication facts by memory. It also decreases the amount of steps they have to accomplish and replacing it with only subtraction.

Upwards Division

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Upwards Division: 532-------- = 177 and 1/33First you are going to see how many times 3 goes into 5. In this problem, 3 goes into 5 one time, so you put a 1 as the first part of the solution.Next, you subtract 3 from the 5 in the numerator. This gives you the number 2. Now you have to take the 2 and put it in front of the 3 (5232) to make it 23.Next, you see how many times 3 goes into 23. Three goes into 23 seven times, so you put the 7 next to the number 1 in the solution.Now you do the same step as before and do 23-21 which equals 2 and you have to put that 2 in front of the 2 (5322).Just like before, you now see how many times 3 can go into 22 and it is 7. Add the 7 to the solution and subtract 22-21. This leaves you with 1 over 3 or 1/3.Add the 1/3 to the solution and now you have the completed answer which is 177 and 1/3.

Week 8

Divisibility Rules

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Divisibility Rules:2- Even number (end in 0, 2, 4, 6, 8, ...) Example: 4,862 3- The sum of the digits is divisible by 3Example: 564 = 15 when added up and 15/3 = 54- If the last 2 digits are divided by 4 Example: 6,7365- Last digit is a 5 or a 0Example: 3,530 or 5,6856- If both divisibility rules 2 and 3 work, then 6 works tooExample: 342 = 9 when added up and 9/3 = 38- If the last three digits divide by 8Example: 13,6489- The sum of the digits is divisible by 9Example: 6,327 = 18 when added up and 18/9 = 210- Last digit is 0Example: 2,980

Showing Integers using 2 colored counters

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To get these problems correct, you have to add zeros which means adding in the addition and the subtraction symbols to cancel each other out. What I do when completing these problems is start by counting out the first number given because that is what we are being asked to show.After that, I add in my zeros by counting each symbol to make sure I am using the correct amount. Show 6 using 8 symbols --> For this problem I typed out 6 + + + + + + + plus signs and then added in another - plus and minus sign. This used 8 symbols, but shows 6 positives because the extra + and - cancel out.Show -3 using 7 symbols - - - - -+ +Show 5 using 9 symbols+ + + + + + +- -

Adding

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7 + 4+ + + + + + + + + + + = 11-3 + 6- - - + + + + + + = 35 + (-2)+ + + + + = 3- - -2 + (-8)- - - - - - - - - - = -106 + (-4)+ + + + + +- - - -

Adding Algorithm (Hector's Diagram)

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If the signs are the same, we addIf the signs are different, we subtractThe sign that is left out is the sign that we put in front of our answer, so if it is a - then the answer is negative, but if the sign left is + then it is positive.+ + - = subtract25 + (-12) = 13+ - - = subtract38 + (-54) = -16 - - - = add-40 + (-64) = -104

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