In Casey's matematica book, one of the exercises is: 4 da e 6 U = ?

The answer is 46.

Our question is what does the da and U mean? We know how to do the problem but would like to know how to read the question. Thanks!

da stands for "decine" (10)
U stands for "unità" ("units" 1)
so 4x10 plus 6x1 is 46

Amica Giulia
Grazie un'altra volta!

Good thing you asked Giulia! Having never gone to elementary school in Italy, I didn't know either.

I did go to Elementari her ein italy, but I would not have been able to answer either!

Very interesting.
And I'll bet you thought you had seen all of the "New Math" there was.
Have you heard about the "Lattice Multiplication" they are teaching in grade school now?

No idea about the Lattice Multiplication but Decine and Unità were very normal for me in primary school about 25 years ago... but it was a Montessori school so I'm not sure about other schools in Italy.

Other schools too. I clearly remeber using a "pallottoliere", how is that called in English?

Boh!

Abacus?
The pallottoliere is the easy version of an abacus but I don't know if there's a specific word in English for that.

I think "counting frame" would be a good translation.

Oh man, the first time Gianna came home with the da and u stuff I kept saying to myself, I am a math major, I can do this, I can figure it out, I got that it was groups of tens and groups of units but I just thought it was a complete waste of time. Then there are the rules, you have to use a red pen for the units, a blue pen for the decine and a green pen for the hundreds.