Tag Archive: sets

How to Teach Subitizing: 1 – 4

Subitize Card 3 ©2011 Bon Crowder

Some thoughts on learning and teaching subitizing. Including 17 downloadable 4×6 flashcards that you can use to teach your child to subitize – assess the quantity without counting!

Union, Intersection and the Empty Set

Union and Intersection

Check out this way to see how union and intersection work – using SnackTraps and blocks. Also, how the empty set works with them!

[50 Word Friday] Math People Think Alike!

This 50 word mini-article is inspired by the coincidence of my post about empty sets coinciding with the Math Dude’s podcast this week.

Empty Sets – When to Use Curly Brackets

If Ø is the same as {Ø} then you shouldn't be grossed out about doing this with your leftovers.

Sets are intuitive – you have a basket and you put stuff in it. But what about the empty basket? How do you write it? And why is that important how you write it? Here’s a hands on example of the empty sets in your kitchen.

Why Learning to Subitize Is Important

©2011 Bon Crowder

Learning to subitize is more important than learning to count – and knowing how to subitize comes before learning to count!

Counting with Ordinal Numbers

MathFourVideoOrdinalNumbers

Ordinal numbers are “1st, 2nd, 3rd, …” but we need these to count items to arrived at the final cardinal numbers. All this fancy math talk – why not make it fun with some colorful bugs!

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