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Use parts to subtract and addition to check.
Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.
Find the part left or the part removed from a known whole.
| Term | What it means |
|---|---|
| difference | The result of subtracting. |
| check | Another way to see whether an answer fits. |
Build seven counters. Move three to the side. Four remain. The starting seven is the whole; three and four are its parts. We write 7 - 3 = 4. If you know the parts, you can subtract without recounting everything. Three taken from seven leaves four.
Another way: picture
Whole: ● ● ● ● ● ● ●. Parts: ● ● ● | ● ● ● ●.
Put the two parts back together. Four and three make seven, so the subtraction fits. Practice within five: five minus two leaves three; five minus three leaves two. Cover a part and name it, then uncover to check. Taking away zero leaves the whole. Taking away all the counters leaves zero. Never begin a new count with the removed part when the question asks what remains.
Separate two from five. [Three counters stay and two move aside]
5 - 2 = 3
Three counters remain.
Rejoin the two parts.
3 + 2 = 5
The check restores the starting amount.
Show the whole and remainder.
4 whole; 1 stays
The missing part is what moved away.
Find the removed part.
What is 6 - 5?
Answer:
Match each subtraction to what remains.
| 6 | 5 | 4 | |
|---|---|---|---|
| 7 - 1 | |||
| 7 - 2 | |||
| 7 - 3 |
Audio transcript: None
Find the part taken away.
8 - p = 5
Audio transcript: None
8 toy animals enter a pen. 4 move to another pen. How many stay in the first pen?
Answer:
Lesson test: one question per skill, one attempt each, no hints. Your answers are checked when you submit.
What is 4 - 1?
Answer:
Split five into two parts. Hide one part and explain how to find it again.
6. Find 4 - __ = 1., step 2
3; 1 + 3 = 4
The parts must make four.