Arithmetic Operations

	COMPARING NUMBERS (for estimation and quick calculation)

	ADDITION & SUBTRACTION DOING AND UNDOING

	MULTIPLICATION AND DIVISION DOING AND ONDOING

ADDING by counting up (helpful for small differences)	ADDING Place-Value blocks Rigt-to-Left (traditional pencil and paper)	ADDING Place-Value blocks Left-to-Right (helpful for fast & mental calcs)	ADDING one Place-Value with mechanical rack&pinion (used in 20th Century mechanical calcs)

SUBTRACTING by counting down (for small differences in mental, and pencil and paper)	SUBTRACTING Place-Value block vie w (helpful for fast & mental calculation)	ROUNDING NUMBERS (for estimation and quick calculation) Worksheets	A FRACTION OF A NUMBER
			Repeated effects and exponents

	MULTIPLICATION - Repeated Add	With SYMBOLS - IN BLOCKS	With SYMBOLS	MULTIPLICATION - With Fractions