A mark on the paper box reads: MILTON BRADLEY (/) NEW MATH (/) FLASH CARDS (/) SUBTRACTION. Another mark reads: [copyright] 1965. A third mark reads: 4592. These and several other sets of flash cards ...

Count back & use the relationship between addition and subtraction to subtract within 20. ... Math Mights. Subtraction Strategies. S2 Ep208. Fixed iFrame. Width: in pixels px Height: in pixels px.

From the 1950s, particularly after the launch of the Sputnik satellite in 1958, American mathematicians and mathematics educators introduced a variety of reforms in mathematics teaching dubbed “The ...