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1.02 — Adding on the Number Line. 45 KB, ten figures, seven printed pages.
The spine: every sum is two instructions, never one. Start at p. Jump q. Size tells you how far, sign tells you which way. That framing is set up in Figure 1 with a generic p-and-q diagram, then applied unchanged through four cases — both positive, adding a negative, starting negative, both negative — so the hard case arrives as the fourth repetition of something familiar rather than a new rule.
The misconception figure. Your map flags “applying multiplication sign rules to addition: −3 + −4 = 7.” Figure 7 puts the two walks on stacked number lines. The wrong one starts at zero — not at −3 — and jumps right twice with dashed arrows labeled "3" and "4" in quotes, landing on 7 in a red ring. The right one starts at −3 and jumps 4 left to −7. The text under it names exactly what the wrong walk threw away: where you were standing, and both directions.
The check students get: if both numbers are negative, the answer must be negative and further from zero than either one. That’s a sign test they can run before computing.
Two things carry across skills. Figure 6 brings back the chips from 1.01 — seven reds, no yellows, nothing to cancel — and Figure 8 shows −4 + 4 = 0 as a walk, so the zero pair they learned last lesson reappears as a special case of this one. Figure 10 looks ahead to 1.03 with −1.5 + 4 = 2.5: same walk, you just stop between the ticks.
Use this in your own class
Copy the code, then in Sleedu: add a Page, click the <> source-code button in the editor, and paste it in.
