Mathematics 3º ESO

Methods to solve simultaneous equations

2012-01-29T21:18:00.002+01:00

Thesevideos demonstrate how to solve simultaneous equations by graphing, bysubstitution and by elimination.

Solvingsimultaneous equations by graph

http://www.youtube.com/watch?v=cqBwozd8nu8

Solvingsimultaneous equations by substitution

http://www.youtube.com/watch?v=8ockWpx2KKI

Solvingsimultaneous equations by elimination

http://www.youtube.com/watch?v=XM7Q4Oj5OTc

Unit 6: Simultaneous equations

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Unit6: Simultaneous equations

Math Word Problems. Equations

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Remember the steps to solve math word problems:
1. Read the problem entirely (get a feel for the whole problem).
2. List information and the variables you identify (attach units of measure to the variables).
3. Define what answer you need, as well as its units of measure.
4. Translate the wording into a numeric equation.
5. Solve the equation.
6. Check your solution using the problem (not your equation).

’MathWord Problems. Equations’ Worksheet

’MathWord Problems. Equations’ Worksheet. Answers

Equation Word Problems. Quiz Show

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Working individually:

Equation Word Problems. Quiz Show

Working in groups:

Make 4 people groups (for example).

One student chooses a card, the teacher reads the problem and all groups have to solve it.

The group that first solves the problem gets 1 point, and so forth.

Cards Quiz Show. Equation Word Problem s

Quadratic Formula Song

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Learning Math trough music!

I'm sure you will be able to learn the quadratic formula by listening to this song.

Problem of the week: Even so

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Answer to the problem of the week: Take three from five

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TAKE THREE FROM FIVE

Choose any five positive whole numbers.
Can you select three that will add up to a multiple of 3?

For example:
If you start with 3, 7, 11, 16 and 20, you can select 3, 7 and 20 which add up to 30.

Choose another five positive whole numbers.
Can you select three again that will add up to a multiple of 3?

Is it always possible to find three numbers that will add up to a multiple of 3 from any set of five positive whole numbers?

Can you explain why?

Answer

Unit 5. Equations

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Unit 5: Equations

Algebraic Language Quiz

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Here you are the questions of the quiz that we did in class.

Algebraic Language Quiz

Problem of the week: Take three from five

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Answer to the problem of the week: Christmas Tree

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CHRISTMAS TREE
The students of the IES Don Bosco are going to make a Christmas Tree using recycled materials. The idea is to make round cardboard trays and to fill them with cans (soft drinks, beer, …). The height of the tree is 216 cm.
The height of a can is 11.5 cm and the thickness of the trays is 5 mm. How many trays will they need to make this tree?
The radius of the top tray is 9.5 cm and the radius of the bottom tray is 69 cm. If the difference between the radiuses of two consecutive trays is always the same, what will be that difference and what will be the radius of each tray?
The sequence of these radiuses is a particular type of sequences. Could you find out the name of these sequences?

Answer

Introducing proof

2011-12-01T12:06:00.001+01:00

This spread will show you how to:
- Understand the difference between a practical demonstration and a proof.
- Recognize the importance of assumptions when deducing results.

Introducing proof
Introducing proof. Worksheet

Problem of the week: Christmas Tree

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Answer to the problem of the week: 20 right triangles and 1 square

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20 RIGHT TRIANGLES AND 1 SQUARE

Cut out 20 equal right triangles. The legs of these triangles are 8 cm and 4 cm.

Put them all together to form a square.

Answer

Problem of the week: 20 right triangles and 1 square

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Answer to the problem of the week: Sticky numbers

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STICKY NUMBERS

Look at the following row of numbers:

10 -15 -21- 4- 5

They are arranged so that each pair of adjacent numbers adds up to a square number:

10 + 15 = 25

15 + 21 = 36

21 + 4 = 25

4 + 5 = 9

Can you arrange the numbers 1 to 17 in a row in the same way, so that each adjacent pair adds up to a square number?

Can you arrange them in more than one way? If not, can you justify that your solution is unique?

Answer

Relationship between odd numbers and squares

2011-11-13T20:22:00.001+01:00

Have a guess!
What is the relationship between odd numbers and squares?
Odd numbers: 1, 3, 5, 7, ...
Squares: 1, 4, 9, 16, ...

You can check your guess watching this video:

% Increase and decrease. Worksheet

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% Increase and decrease. Worksheet
% Increase and decrease. Worksheet (Answers)

Unit 4: Algebraic language

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Unit 4: Algebraic language

Problem of the week: Sticky numbers

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Answer to the problem of the week: Where did the dollar go?

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WHERE DID THE DOLLAR GO?

Three friends have a nice meal together, and the bill is $25. The three friends pay $10 each, which the waiter gives to the cashier. The cashier hands back $5 to the waiter.

But the waiter can’t split $5 three ways, so he gives the friends one dollar each and keeps 2 dollars as a tip.

They all paid $10 and got $1 back. $10 - $1 = $9

There were three of them. 3 · $9 = $27

If they paid $27 and the waiter kept $2: $27+ $2 = $29

Where did the dollar go? $30 - $1 = $29

Answer

Unit 2: Numbers and their uses (II)

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Unit 2: Numbers and their uses (II)

Problem of the week: Where did the dollar go?

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Answer to the problem of the week: Three cyclists

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THREE CYCLISTS

A team of three cyclists takes part in a race.
The cyclists Jan, Kim and Ryan do the distance in the ratio 7:3:4. Kim cycles 177 km.

a) How far does Jan cycle?
b) How far is the race?

Answer by Raquel González García

Answer by Resu Rodríguez Segovia

Answer

Problem of the week: Three cyclists

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Ratio and proportion

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Learn more about ratio and proportion

Ratio and proportion

Finding fraction parts

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Imagine you have a recipe with ingridients for 4 people. This activity will help you find the amounts needed to make this recipe for a different number of people.

Finding fraction parts

Answer to the problem of the week: Science, Maths and French

2011-10-07T19:40:00.000+02:00

SCIENCE, MATHS AND FRENCH

There are 50 students in the 7th grade who study Science, Math and French.

Of these, 24 students in all study Science; 20 in all study Math and 22 students in all study French.

Of these students, 4 study Science and Math but not French; 3 study Science and French but not Math; and 5 study French and Math but not Science.

Only 2 students study all three subjects.

How many students take only Science? _______
Only Math? ________
Only French? ________

Answer by Raquel González García

Answer by Victor Plaza Verdú

Venn diagrams are a useful way to represent sets. In this video you can see how use them in order to solve the problem of the week: Science, Maths and French.