Welcome to level 7 ### Welcome to level 7 By the end of this lesson, you can: * use maths in Hedy * use decimal numbers in Hedy * use variables in maths in Hedy <aside class="notes">Ask your students to predict when they would need maths in a code (for example calculating a price, an amount of people, points in a game etc). You could also ask them to predict what this would look like. They will most likely come up with + and - themselves.</aside>

Addition ### Addition If you want to calculate an addition, simply use the plus sign. <iframe class="fragment" src="/render_code/7?code=print%20%275%20plus%205%20is%20%27%205%20%2B%205"></iframe> <aside class="notes">Briefly show your students the example code.</aside>

Subtraction ### Subtraction If you want to subtract, you can use the minus sign. <iframe class="fragment" src="/render_code/7?code=print%20%275%20minus%205%20is%20%27%205%20-%205"></iframe> <aside class="notes">Briefly show your students the example code.</aside>

Multiplication ### Multiplication If you want to do multiplications, you can use the asterisk. <iframe class="fragment" src="/render_code/7?code=print%20%275%20times%205%20is%20%27%205%20%2A%205"></iframe> <aside class="notes">Briefly show your students the example code.</aside>

Division ### Division You can use the slash for division. <iframe class="fragment" src="/render_code/7?code=print%20%275%20divided%20by%205%20is%20%27%205%20/%205"></iframe> <aside class="notes">Briefly show your students the example code.</aside>

Summary ### Summary In summary, you can use +, -, * and / to do maths. <iframe class="fragment" src="/render_code/7?code=print%20%275%20plus%205%20is%20%27%205%20%2B%205%0Aprint%20%275%20minus%205%20is%20%27%205%20-%205%0Aprint%20%275%20times%205%20is%20%27%205%20%2A%205%0Aprint%20%275%20divided%20by%205%20is%20%27%205%20/%205"></iframe> <aside class="notes">Please note that the maths code does not need quotation marks. Let your students predict what the output would look like if you did puth the maths code inside the quotation marks.</aside>

The = symbol ### The = symbol From now on you can also use the = symbol instead of the `is` keyword. This goes for both numbers and words, and it also goes after the `if` or `else` keywords. <iframe class="fragment" src="/render_code/7?code=name%20%3D%20Hedy%0Aanswer%20%3D%2020%20%2B%204"></iframe> <aside class="notes">Briefly show your students the example code.</aside>

Calculations with variables ### Calculations with variables You can use calculations with numbers, but you can also use variables to do calculations, like this: <iframe class="fragment" src="/render_code/7?code=number_1%20%3D%20ask%20%27Fill%20in%20the%20first%20number%3A%27%0Anumber_2%20%3D%20ask%20%27Fill%20in%20the%20second%20number%3A%27%0Acorrect_answer%20%3D%20number_1%20%2A%20number_2%0Aprint%20number_1%20%27%20times%20%27%20number_2%20%27%20is%20%27%20correct_answer"></iframe> <aside class="notes">Show the students the example code and have them take a look at the placement of the quotation marks. If you've made them come up with some examples of how to use maths in Hedy in the previous slides, ask them what they think this code would look like. For example, if a student came up with the answer 'calculating points of a game' they could now come up with the code: ``` if answer = correct_answer points = points + 1 else points = points - 1 ``` If you think this is too hard for your students to do individually or in pairs, you could do this exercise together with the whole class.</aside>

Decimal numbers ### Decimal numbers So far, Hedy did not allow for decimal numbers like 1.5, but now we do allow that. Note that computers use the . for decimal numbers. <iframe class="fragment" src="/render_code/7?code=print%20%27Two%20and%20a%20half%20plus%20two%20and%20a%20half%20is...%27%0Aprint%202.5%20%2B%202.5"></iframe> <aside class="notes"></aside>

Debugging ### Debugging Let's debug this code! <iframe class="fragment" src="/render_code/7?code=print%20%27This%20is%20the%20water%20park%20ticket%20machine%27%0Aprint%20%27Price%20list%3A%20Children%20under%2012%20%243%2C%20Adults%20%245%27%0Aprint%20%27Mondays%20are%2025%25%20off%27%0Aamount_of_children%20%3D%20%27How%20many%20kids%20tickets%20would%20you%20like%3F%27%0Aamount_of_adults%20%3D%20%27How%20many%20adult%20tickets%20would%20you%20like%3F%27%0Aday_of_the_week%20%3D%20ask%20%27What%20day%20is%20it%3F%27%0Aclear%0Achild_price%20%3D%20amount%20of%20children%20%2A%203%0Aadult_price%20%3D%20amount_of_adults%20%2B%205%0Atotal_price%20%3D%20adult_price%20%2A%20child_price%0Aif%20day%20is%20monday%0Atotal_price%20%3D%20total_price%20%2A%200.25%0Aprint%20%27That%20will%20be%20total_price%20please%27"></iframe> <aside class="notes">Debug this code together with your students.</aside>

Let's get to work! ### Let's get to work! Enjoy the adventures in level 7! <aside class="notes">The students can now make all the adventures in this level.</aside>

Let's review! ### Let's review! Which adventure did you like best? Why? Which adventure did you like least? Why? <aside class="notes">Ask the students for their opinion.</aside>

Let's review! ### Let's review! What did you learn today? <aside class="notes">Ask the students to list what they've learned today.</aside>

Show and tell! ### Show and tell! Would anyone like to show the class a program they've made? <aside class="notes">Let some students show their work to the class.</aside>

Sneak peek into the next level... ### Sneak peek into the next level... In the next level you'll learn how to repeat a line of code multiple times! <aside class="notes"></aside>