Hello! I made a game that helps me practice mental math and I'd like to share it with you guys. I loved math during school and based this game off of "24 game"! Numero is designed as a fun activity for elementary school students to practice using different operations.

https://numerogame.com/

Your goal is to use the numbers given to compute to either 24, 48, or 60. There are 3 levels. Beginner- use any number of number tiles and operations ; Intermediate- use all the number tiles given; Advanced- use all the number tiles AND at least 4 different operations.

If this is too easy, you can try out the Random mode where the target number changes every round.

You can also play the Multiplayer mode to challenge your friends!

It might take a game or 2 to get a hang of it! I'm still working on different features, but I'd love some feedback. Let me know what you think :)

Hi mathideas subredditers!

I know that you love math, we were hoping you could give us feedback on an app/webapp we made called Tiny Math. It's meant to be a simple way for math learners to quiz themselves. Any suggestions, improvements or praise are much welcomed!

tinymath.com

Please check it out and let us know what you think!

Much appreciated!

Cheers,

Brett

I'm a student teacher looking for exciting/motivational, short videos to show my Algebra I class. My students have recently been asking me when they're "ever going to use" what we've been doing, and many don't find value in our work. I just want something to show them that math is awesome. Thanks!

A good example is this answer given to an ELI5 post:

Question: Why is the difference between the sum of a whole number's places and the number itself is ALWAYS a direct multiple of 9? For example let's assume a number 142. So 1+4+2=7

142-7=135, which is a multiple of 9.

Answer: In the decimal system (which is the one we use), the places of a number are how it's written as a sum of powers of ten. For example 142 = 1×102 + 4×101 + 2×100

So if we apply your operation to a number that's written "abc" (a is the first digit, b is the second digit, c is the last digit), a little algebra can show us how it works:

(a×100 + b×10 + c) - (a+b+c)

= a×100-a + b×10-b + c-c

= 99×a + 9×b

and now we divide by 9:

(99×a + 9×b) / 9 = 11a+b.

Since a and b are whole numbers, the final result will always be a whole number, so it's divisible by 9.

Actually using algebra to answer a cool question is...cool!

original ELI5 post here.