Chapter 7 The Study Of Numbers Up To 20
FIG 71. Does the difference remain the same whichever rod we add to both lines? Take away the white and the yellow rods and try any other rod. Try orange rods. Try two orange rods. 2 Can you tell me from memory the answer to 17 â€“ 9 = ? Set out a rod pattern for this.
FIG. 72. Add a white rod to each line of your pattern.
Published on Nov 18, 2009