Remember: To sort, compare two neighbors and swap them if they are out of order. Go along the whole row, then do it again, and stop when a whole pass needs no swaps.
Read and answer
Read the story, then answer.
Two at a timeJonah's five robot cards for open day stand in a jumble on his shelf: 4, 2, 5, 1, 3. Each card is a different height, and he wants them from smallest to biggest. Bo wants to help, but he can only see two cards at once. So here is Bo's trick: look at two cards that sit side by side. If the bigger card is on the left, swap them. If they are already in order, leave them alone. From the left, Bo swaps four and two, but four and five can stay. Next he swaps five and one, and then five and three. That trip along the whole row, pair by pair, is one pass. Bo makes another pass, and then another, and each time fewer cards need swapping. When a whole pass has no swaps at all, the row is sorted.
1
Jonah's five cards stand in a row: 4, 2, 5, 1, 3. Bo looks at the first two cards, 4 and 2. What does he do?
Leave themSwap themTake the 2 away
2
Bo can see the whole row at once.
TrueFalse
3
After the first swap, the row is 2, 4, 5, 1, 3. Bo looks at 4 and 5. What does he do?
Swap themTake the 5 awayLeave them
4
After the first pass, the biggest card, 5, has floated to the of the row.
endstartmiddle
5
Which row shows the cards after one whole pass?
2, 4, 5, 1, 31, 2, 3, 4, 52, 4, 1, 3, 5
6
Each pass sends the biggest card that is left over to its place.
TrueFalse
Pass after pass
7
Put the swaps of pass one in order, for the row 4, 2, 5, 1, 3.
Swap 5 and 1
Leave 4 and 5
Swap 4 and 2
Swap 5 and 3
8
The row after pass one is 2, 4, 1, 3, 5. Which row shows it after pass two?
2, 1, 3, 4, 51, 2, 3, 4, 52, 4, 1, 3, 5
9
The row is sorted when a whole pass needs swaps.
noonefive
10
Look at this row as it stands. Circle every pair of neighbors where the bigger card is on the left.
3 and 66 and 22 and 55 and 88 and 7
11
Mix-up to fix: after one pass on 4, 2, 5, 1, 3, Jonah says, "2, 4, 1, 3, 5 is sorted, so I stop." What should he do?
Keep making passes until a pass needs no swapsSwap the 2 and the 4 backStart again from the original row
12
Stretch: Bo sorts the row 3, 1, 2 with his trick. Counting the last pass that has no swaps, he makes passes.
13
Line up five things like spoons or books. Sort them the robot way, two neighbors at a time, and write how many passes it took.
14
Draw Jonah's five cards as a staircase from smallest to biggest.
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Answer key · Set A
Bo sorts the cards
1Swap them The bigger card, 4, is on the left, so Bo swaps them.
2False Bo can only compare two cards at a time.
3Leave them 4 is smaller than 5, so the pair is already in order and Bo leaves it alone.
4end Each pass sends the biggest card that is left over to its place.
52, 4, 1, 3, 5 Pass one swaps 4 and 2, leaves 4 and 5, swaps 5 and 1, and swaps 5 and 3. That gives 2, 4, 1, 3, 5.
6True That is why the 5 reaches the end in pass one.
73, 2, 1, 4 Bo goes along the row from the left, one pair at a time: 4 and 2, then 4 and 5, then 5 and 1, then 5 and 3.
82, 1, 3, 4, 5 In pass two, 2 and 4 stay, 4 and 1 swap, 4 and 3 swap, and 4 and 5 stay. That gives 2, 1, 3, 4, 5.
9no When a whole pass has no swaps at all, the row is sorted.
106 and 2, 8 and 7 6 is bigger than 2 and sits on its left, and 8 is bigger than 7 and sits on its left. The other pairs are in order.
11Keep making passes until a pass needs no swaps One pass may not be enough. 4 and 1 and 4 and 3 are still out of order.
122 Pass one swaps 3 and 1 to give 1, 3, 2, then swaps 3 and 2 to give 1, 2, 3. Pass two has no swaps at all, so the row is sorted after 2 passes.
13Your own words: a grown-up reads it.
Mark each answer, count the right ones and write the score on the sheet.