Do I really need to make dd use unit multipliers?

[PrairieAir]

We are just starting Algebra 1/2 in Saxon. Yes, she's had to use them before, but I've let her just figure problems out her own way as long as she gets them right. Using unit multipliers is certainly not the way I do conversions and it seems like adding extra steps. Is there a reason for her to do it this way? If she goes to public school in the future, will they require her to do work this way? Will it come up on standardized tests? Really, I don't ever remember being taught to do these types of problems this way. She's frustrated and confused by it and I can understand her position!

[PrairieAir]

Just bumping this up before we start math for the day.

[Jann in TX]

For simple conversions I tend to use my 'own' methods--the ones I was taught in school...

But the majority of students WILL make errors when it comes to converting square or cubic units. The Unit Multiplier method helps the students 'see' all of the pieces.

I've seen the Unit Multiplier method in several other math AND science texts.

Donna Young used to have a simple explanation on her site--it is probably still there.

If your students can come up with the CORRECT answer using their own methods then go for it--but again--watch out for the next level of conversions...you might change your mind about this method!

Jann

[PrairieAir]

This is what I was wondering about--the next level and use in other texts besides Saxon. I think I'll just make her use this method when it specifically asks for it. Otherwise she can use her own. Basically, it's the same thing, it's just not written out the same way and more is done mentally.

[WTMindy]

she understands what she is doing at a conceptual level. There is nothing magical about Saxon's particular method, although I do think it is good to see the units canceling out so that you know whether to multiply or divide the numbers. If she understands what she is doing then I wouldn't make her do it. If you sense she is just kind of winging it a bit, then I would make her write it out. The ones where it gets tricky are when you are converting to cubic meters and you have to multiply by 3 of something. It helps to see why you do that.

[AndyJoy]

in both my high school and college chemistry courses. Knowing how to covert without it is good, but when you're doing long strings of conversions, unit multipliers are invaluable for organizing your work.