Two Substituting Firsts, This Week

[royable]

9. In this case, the x is the unknown. It could by y or z or a or gamma or a box.

I remember doing worksheets in 2nd grade where we had to write the answer inside a big open box of triangle or circle.

[BOX] + 7 = 12

3 * [CIRCLE] = 18

(where the "*" above is a multiplication sign)

Little did we know that we were being mentally prepared for 7th grade pre-algebra.

So in 7th grade we're given problems like

x + 7 = 12

3 * x = 18

and the very same classmates I'd had in 2nd grade were getting all bent out of shape. "Oh, algebra, it's SOOOO hard!" And I'd remind them we did this in 2nd grade, except we got to write the number inside a hollow shape instead of writing "x = whatever" on a separate line.