For each question, explain or show your reasoning. Use a number line if it is helpful.
Is 106 greater or less than 21?
Is 1211 greater or less than 1?
Show Solution
Greater than 21. Sample response: I know that 105 is equivalent to 21 and 106 is greater than 105.
Less than 1. Sample response: I know that 1212 is 1 and 1211 is less than 1212.
Section A Check
Section A Checkpoint
Problem 1
Label the point on each number line with a fraction it represents.
Show Solution
87. There are 8 equal parts in 1, and the point is on the 7th tick mark from 0 to show 7 parts.
58. There are 5 equal parts in each whole, and the point is on the 8th tick mark from 0 to show 8 parts.
Problem 2
Is 127 greater than or less than 21? Explain your reasoning. Use the number line if it is helpful.
Show Solution
127 is greater than 21. Sample responses: 127 is the 7th tick mark from 0 on this number line, and it’s more than halfway to 1. Half of 12 is 6 and 21 is 126, so 127 is greater.
Problem 3
Explain why 124 is equivalent to 31. Use the number line if it is helpful.
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Sample response: If I divide each third into 4 equal pieces, each of those pieces is 1 twelfth, and 31 is on the 4th tick mark from 0, showing it is equivalent to 4 twelfths.
Name two fractions that are equivalent to 35. Explain or show your reasoning.
Show Solution
Sample responses:
610. I drew a tape diagram to show 5 thirds. Then I partitioned each 1 third into 2 equal parts, so in 5 thirds there are 10 parts. Each part is 1 sixth, so in 5 thirds there are 10 sixths.
1220. I drew a tape diagram to show 5 thirds. Then I partitioned each 1 third into 2 equal parts to make sixths and then each 1 sixth into 2 equal parts again to make 12 parts. Each part is 1 twelfth, so in 10 sixths there are 20 twelfths.
Name a fraction that is equivalent to 43. Explain or show your reasoning. Use a number line, if it helps.
Show Solution
Sample responses:
86, 129, or equivalent. If using a number line, students may partition it into fourths, and further partition each fourth into 2 parts to get eighths or into 3 parts to get twelfths.
Explain or show why this statement is true: 45 is equivalent to 1215. Use a number line, if it helps.
Diego wrote 511 and 1055 as equivalent fractions. Are those fractions equivalent? Explain or show how you know. Use a number line, if it helps.
Show Solution
Sample responses: Students may use number lines to show their reasoning.
When I split each fourth into 3 equal parts, I can see that 3× 5=15. Splitting each fourth into 3 equal parts makes twelfths, and 5 fourths is the same size as 15 twelfths.
No, 1 fifth can be partitioned into 2 parts to get tenths, so 11 fifths has 11×2 or 22 tenths, not 55 tenths.
List two fractions that are equivalent to 43. Explain or show your reasoning.
Show Solution
Sample response: 86 and 129. Each 41 is the same size as two 81s. So, three 41s is the same size as six 81s. Each 41 is the same size as three 121s. So, three 41s is the same size as nine 121s.
Problem 2
List two equivalent fractions that the point represents. Explain your reasoning.
Show Solution
Sample responses: 61 and 122. There are 6 equal parts on the number line and the point is the first tick mark, so that’s 61.
The point is the second tick mark when I divide each 61 into 2 equal parts. Those parts are 121s because there are 12 in 1 whole. So, the point is also 122.
Problem 3
To show that 127 is equivalent to 2414, Kiran wrote: 2×122×7=2414. Do you agree with Kiran? Explain your reasoning.
Show Solution
Yes, I agree with Kiran. Sample response: 127 is 7 equal parts when there are 12 of those parts in 1 whole. If I partition each of those 12 parts into 2 smaller parts, then I get 2×7 of the smaller parts with 2×12 of them in the whole. That’s 2×122×7.
Put these fractions in order, from least to greatest. Show your reasoning.
125
68
104
57
Show Solution
104, 125, 68, 57. Sample response:
104 and 125 are less than 1. 68 and 57 are greater than 1.
Comparing 104 and 125: 10×64×6=6024 and 12×55×5=6025, so 125 is greater.
Comparing 68 and 57: 6×58×5=3040 and 5×67×6=3042. Or: 68 is 62 more than 1, while 57 is 52 more than 1. Since 52 is greater than 62, 57 is greater than 68.
Use a >, <, or = symbol to make each statement true. Explain your reasoning.
1241131
1005311125
100265111028
8131157
Show Solution
Sample responses:
124=31, because 31 is the same as 3×41×4, which is 124.
10053>125, because 10053 is more than 21, and 125 is less than 21.
100265<1028, because 1028 is 100280.
813>57, because if I take away 1 from each then I have 85 and 52. I know 85 is greater than 21, and 52 is less than 21.
Problem 2
Clare walked 54 of the way around a lake. Tyler walked 127 of the way around a pond. Explain why you don’t have enough information to determine who walked farther.
Show Solution
Sample response: I know that 54 is greater than 127 because 54 is close to 1 (or is 51 less than 1) and 127 is just a little over 21 (or is 121 more than 126, which is 21). But I don’t know how far it is all the way around the lake or the pond. If the pond Tyler is walking around has a much longer distance than the lake Clare is walking around, then Tyler could be walking farther.