| 摘要 |
An improved numeracy and place-value educational device which accurately displays both whole-number and decimal place-value properties. A conventional counting-wheel odometer comprising a plurality of sequentially numbered counting wheels (10a- 10f) and motion transfer components (not shown) is supported by a frame (12). A decimal carrier (20) moves laterally across an I-beam portion (16) of the frame. The lateral movement allows a decimal point (20') to precede or follow any numeral in a specific row displayed by the counting wheels (10a-10f). A place value band (18) displays place value names (19a- 19f). Its movement, in unison with the decimal carrier (20) and a moveable comma (24'), maintains the correct orientation of place-value names (19a-19f) in relation to the decimal point (20'). Force is applied via a hand crank (14) to the motion transfer components which selectively rotate the counting wheels (10a-10f). A sequential, dynamic display of both whole-number and decimal place-value properties is presented consistently, accurately, and in an objective fashion. |
