#order of operation

[flyingiseasy-landingnotsomuch]

[alwaysmathematics]

Place value, ordering and rounding

Multiplying and dividing decimals mentally

Multiply decimals can be tricky yet it can be as simple as multiplying whole numbers. My steps on multiplying decimals:

count how many digits available after the decimal point from numbers you want to multiply. Store that info.

ignore the decimal point (the decimal numbers become whole numbers). Do the multiplication between numbers.

return the decimal point based on the info from step 1

For example: 0.3 x 5. (1) In total from these two numbers, we have 1 digit behind the decimal point. It means the result will have 1 digit behind the decimal point. (2) ignore the decimal point of these 2 numbers. 3 X 5 = 15. (3) return the decimal point. How many digit behind the decimal point is for the result? 1. So the answer is 1.5.

Another example : 0.04 x 1.2. (1)In total, we have 3 digits behind the decimal point. It means the result of this calculation will have 3 digits behind the decimal point. (2) ignore the decimal point. 4 x 12 = 48. (3) Based on step 1, the result will have 3 digits behind the decimal point. Hm, the result only has 2 digits! No worries, just add 0 . The result is 0.048.

For dividing decimal, I will use my knowledge on fraction and equivalent fraction . My steps on dividing decimals:

write them as a fraction

find the equivalent fraction with the goal of eliminating decimal point

do the division

Exercise time ! Work these out mentally. The answer will be available at the end of the post.

1.3 x 0.02

24 : 0.04

(12 x 0.2) : (0.3 x 0.2)

Multiplying and dividing by powers of 10

Things you need to remember about powers of 10

Multiply a number by the power of 10 with the negative index is the same as divide the number by the power of 10.

Divide a number by the power of 10 with the negative index is the same as multiply the number by the power of 10.

Exercise :

Rounding

For this topic, you need to understand about the place value, significant figure and decimal place. We jump directly to the example.

If, I want to round 3 451.67 to the nearest whole number, it means I will keep the number until 3 451. Yet, there is a possibility that the last digit 1 changes. Depending on the digit after 1. If the digit after 1 is 5 or more, the last digit of the number will be increased by 1. If not, stay the same. Look on the number, after 1 we have 6. It is more than 5. So the last digit is increased by 1. The result is 3 452. The result will be until the digit that takes the position of the nearest whole number.

Another example using the same number. I will round the number to 3 significant figures (3 S.F.). I will keep the number until 3 45. Now, check the digit after 5. 1 is less than 5, stay the same. After that, check the original value position of 5. It is ten. On the result, 3 45, the 5 takes the position of one. Hm, we need to add something so the 5 takes the position of 10. Yeah, we need to add a 0 after 5. The result is 3 450.

Order of operations.

BEDMAS : Bracket, Exponention (power), Division Multiplication and Addition Subtraction.

Note: if you have division and multiplication or addition and subtraction on the same problem, you need to do it from left to right.

I will give you a problem : work out the value of this expression when x = 2 and y = -3 for 4x^2 - y

The answer is 0.026 ; 600 ; 40 ; 15 000 ; 0.012 ; 342 000 ; 19

See you !

[tetontrekker]

99% of People Will Get This Wrong

99% of People Will Get This Wrong

Solve if you are a genius. Most will get this wrong. All of these are phrases are meant to get you to engage, and it made you click on my blog. Normally I don’t engage with memes like this one, I am too busy to argue with strangers, plus some genius used a U instead of YOU on a hand printed note [cringe emoji]. In this case my cousin shared it and I love arguing with my family, we are all…

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[videoseer]

(via https://www.youtube.com/watch?v=tvjJppmx9Hk)

[khronosz]

My Typical Order of Operation,

Do a warm-up sketch, draw original content, draw fan art, practice facial features, all the works. Nothing is safe in my mind.

Fall in love with a specific styling and idea and draw more around it, eventually erasing everything on the page to add more ideas based around the former.

Cry rivers and stop drawing for a little bit because I can’t erase the troll filled lines of what was there originally. Get over myself and remember the fact we live in the 21st century and have Photoshop.

Convert the entire warm-up page into a stand-alone picture that feigns ‘it was planned like this, I swear.’ Fill the entire page with stylizations and shadings.

Get to the last part of said picture and cringe while you look at a huge section of blank space and mutter, “The <nonsensical cuss word(s) here> do I put here?”

Sit around for a few days and do another warm-up page of ideation to fill the void, rinse and repeat the above.

Optional: Make Tumblr quip about it because you’re procrastinating like a pro.

[slightglimmerofhope]

Ausmuteants "Boiling Point"

I saw these Aussies do a raucous set at The Smell last weekend.

Screamers + early Devo + noise.

[thecalcul8r]

1.4 Order of Operations

PEMDAS

aka

Please Excuse My Dear Aunt Sally

aka

Parentheses, Exponents, Multiplication, Division, Addition, Substraction

I'm pretty sure this is actually 7th grade math. You can see the way they're building up towards factoring, though: x^2+2x+1, (x+1)^2...(sorry about the gross looking exponents). I still associate those expressions with a sense of relief - it's like, if you end up with one of those when you're done working the problem, you know you did it right.

I should have gotten a perfect score on this one. I should have. I understood it perfectly. I did the entire exercise twice. But I still missed one.

(5x2)^3

Twice, I misread the multiplication sign as an addition sign and did 7^3 instead of 10^3. TWICE. In eighth grade, when these kinds of tiny, twitchy mistakes really mattered, I remember the feeling of being tortured by brain demons, little wayward synapses that would sit in the back of my brain and cackle as they messed with me. And seriously, you can see the joke here, right? By misreading the sign, I turned this problem into 7 cubed - the exact same problem I got wrong last time.

I see you, brain demons. I see you. And I am going to make friends with you, and then invite you, very kindly and mindfully, to get lost.

[learnmath]

Why PEMDAS is 'morally' wrong

Here’s a video that explains why you need to memorise PEMDAS or the order of operation and why you don’t need to.

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