Lesson 10 of 19
What zero does
Show on a big screenTake 7 + 0, 7 × 0, 0 ÷ 7 and 7 ÷ 0. One has no answer. Which?
Step 1 of 4
- 7 + 0 = 7. No steps taken.
- 7 × 0 = 0. Nothing, seven times.
- 0 ÷ 7 = 0. Nothing shared seven ways.
- 7 ÷ 0 has no answer.
Only 7 ÷ 0 has no answer.
Rule: adding or taking away zero changes nothing. Times zero is zero. Zero shared into some groups is zero. Sharing into zero groups has no answer.
0 − 7 is not the same as 7 − 0. Taking away 0 changes nothing, so 7 − 0 = 7. Start at zero and walk 7 left: 0 − 7 = −7.
7 ÷ 0 asks: how many empty groups make a pile of 7? An empty group holds nothing. So no count of empty groups makes a pile of 7. That is why 7 ÷ 0 has no answer.
Slide the groups down to 0 in the lab. See which count has no answer.
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Try the lab to finish this lesson.