Tuesday

Arrays

Think about when we line up at school. Is it easier for the teacher to count you all in rows, or when everyone is all over the place:

That's right: rows! Well, all other things are the same: they're easier and quicker to count in rows. There's even some tricks you can use to count things REALLY quickly when they're set up in rows and columns.

When things are set up in rows and columns, they're called ARRAYS. Here's some real-life pictures of arrays:














Arrays are even in Minecraft:

So, here's the trick to count these rows and columns. Count the number in the first row. Count the number in the first column. Multiply those numbers together.




Here's the strategies:

1. If you know your times tables, it's EASY!


2. If you don't, you can split the rows and columns into easier parts, for example split the whole thing in half then try to do that times tables. Or break it into an easier times table that you know:

x x x x  x       x
x x x x x     x
x x x x x     x
x x x x x     x
This one was 4 groups of 6.
The student knew 4 x 5 = 20.
Then add another 4.
= 24.
This is 5 groups of 4, or 5 x 4. If you don't know that, just split it in half to solve:
= 5 x 2 + 5 x 2
= 10 + 10
= 20
Or you could have skip-counted by 5s, but that might have been slower.

3. If you have no way to break up the array using a times table you know, just skip-count to the answer.

Try to use the best strategy you can to solve the arrays you create using this program: Arrays in an instant.

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