Step-by-step Maths Level 2 Comparing and ordering to 100: check-up and practice test questions

Method. Put the numbers in order, smallest to largest. Find the first one and then the next.

1. Look at the tens of each number. The numbers with fewer tens are smaller.
   88: 8 tens, 43: 4 tens, 60: 6 tens, 79: 7 tens
2. Find the first number in the order. It is the smallest, or the largest if we go the other way.
   43
3. Write the numbers in order. Check that each one fits between the ones next to it.
   43, 60, 79, 88

Check. Read the list again. Each number is bigger than the one before.

Watch out. Compare tens first. 52 comes before 61 because 5 tens is less than 6 tens.

Method. Compare the tens first. If the tens are the same, compare the ones.

1. Compare the tens digits. The tens digit is worth the most.
   9 and 3
2. Tens are different, so the tens decide. 9 tens is more than 3 tens.
   9 tens and 3 tens
3. Write the sign. 95 is greater than 34.
   >

Check. 95 > 34 is true.

Watch out. Compare tens first. 61 is greater than 58, because 6 tens is more than 5 tens.

Method. Change the number by the amount in the question.

1. Start with the number. It is the number we change.
   92
2. Change it. Take away one. Count back to the number before.
   92 - 1 = 91
3. Write the answer.
   91

Check. Reverse the change: 91 + 1 gives 92.

Watch out. Ten more changes only the tens digit. One more can change the tens too: 1 more than 59 is 60.

Method. Put the numbers in order, smallest to largest. Find the first one and then the next.

1. Look at the tens of each number. The numbers with fewer tens are smaller.
   82: 8 tens, 93: 9 tens, 26: 2 tens, 96: 9 tens
2. Find the first number in the order. It is the smallest, or the largest if we go the other way.
   26
3. Write the numbers in order. Check that each one fits between the ones next to it.
   26, 82, 93, 96

Check. Read the list again. Each number is bigger than the one before.

Watch out. Compare tens first. 52 comes before 61 because 5 tens is less than 6 tens.

Method. Change the number by the amount in the question.

1. Start with the number. It is the number we change.
   13
2. Change it. Take away ten. The tens digit goes down by one.
   13 - 10 = 3
3. Write the answer.
   3

Check. Reverse the change: 3 + 10 gives 13.

Watch out. Ten more changes only the tens digit. One more can change the tens too: 1 more than 59 is 60.

Method. Change the number by the amount in the question.

1. Start with the number. It is the number we change.
   73
2. Change it. Take away ten. The tens digit goes down by one.
   73 - 10 = 63
3. Write the answer.
   63

Check. Reverse the change: 63 + 10 gives 73.

Watch out. Ten more changes only the tens digit. One more can change the tens too: 1 more than 59 is 60.

Method. Find the greatest number by comparing the tens first.

1. Look at the tens. The numbers with the most tens are the greatest.
   3, 7, 6
2. Check the ones if two numbers have the same tens. The ones decide between them.
   38, 70, 61
3. Choose the greatest. It is the biggest of the numbers in the list.
   70

Check. Put the others in order to check: 70 is the greatest of them all.

Watch out. The number with the largest ones digit is not always the greatest.

Method. Change the number by the amount in the question.

1. Start with the number. It is the number we change.
   58
2. Change it. Take away one. Count back to the number before.
   58 - 1 = 57
3. Write the answer.
   57

Check. Reverse the change: 57 + 1 gives 58.

Watch out. Ten more changes only the tens digit. One more can change the tens too: 1 more than 59 is 60.

Method. Compare the tens first. If the tens are the same, compare the ones.

1. Compare the tens digits. The tens digit is worth the most.
   1 and 8
2. Tens are different, so the tens decide. 1 tens is fewer than 8 tens.
   1 tens and 8 tens
3. Write the sign. 10 is less than 85.
   <

Check. 10 < 85 is true.

Watch out. Compare tens first. 61 is greater than 58, because 6 tens is more than 5 tens.

Method. Put the numbers in order, smallest to largest. Find the first one and then the next.

1. Look at the tens of each number. The numbers with fewer tens are smaller.
   93: 9 tens, 67: 6 tens, 60: 6 tens, 11: 1 tens, 96: 9 tens
2. Find the first number in the order. It is the smallest, or the largest if we go the other way.
   11
3. Write the numbers in order. Check that each one fits between the ones next to it.
   11, 60, 67, 93, 96

Check. Read the list again. Each number is bigger than the one before.

Watch out. Compare tens first. 52 comes before 61 because 5 tens is less than 6 tens.

Method. Change the number by the amount in the question.

1. Start with the number. It is the number we change.
   35
2. Change it. Take away ten. The tens digit goes down by one.
   35 - 10 = 25
3. Write the answer.
   25

Check. Reverse the change: 25 + 10 gives 35.

Watch out. Ten more changes only the tens digit. One more can change the tens too: 1 more than 59 is 60.

Method. Halfway is the number in the middle when we count along the line.

1. Start at 70. It is one end of the line.
   70
2. Count on in ones to the middle. Five steps from 70 reaches the middle.
   71, 72, 73, 74, 75
3. Write the answer. It is the same distance from both ends.
   75

Check. 75 is 5 more than 70, and 5 less than 80.

Watch out. Halfway means the same number of steps from both ends.

Method. Halfway is the number in the middle when we count along the line.

1. Start at 30. It is one end of the line.
   30
2. Count on in ones to the middle. Five steps from 30 reaches the middle.
   31, 32, 33, 34, 35
3. Write the answer. It is the same distance from both ends.
   35

Check. 35 is 5 more than 30, and 5 less than 40.

Watch out. Halfway means the same number of steps from both ends.

Method. Find the least number by comparing the tens first.

1. Look at the tens. The numbers with the most tens are the greatest.
   7, 8, 9
2. Check the ones if two numbers have the same tens. The ones decide between them.
   71, 87, 97
3. Choose the least. It is the smallest of the numbers in the list.
   71

Check. Put the others in order to check: 71 is the least of them all.

Watch out. The number with the largest ones digit is not always the greatest.

Method. Count on from the smaller number. Stop just before the bigger one.

1. Start at 75. The smaller number is where we start.
   75
2. Count on until just before 79. Numbers between come after the smaller one and before the bigger one.
   76, 77, 78
3. Write one of the numbers. Any of these is correct.
   Accept any of 76, 77, 78

Check. Check: any number from the list is bigger than 75 and smaller than 79.

Watch out. Do not write 75 or 79. They are the ends, not the numbers between.

Method. Put the numbers in order, smallest to largest. Find the first one and then the next.

1. Look at the tens of each number. The numbers with fewer tens are smaller.
   99: 9 tens, 56: 5 tens, 14: 1 tens, 75: 7 tens
2. Find the first number in the order. It is the smallest, or the largest if we go the other way.
   14
3. Write the numbers in order. Check that each one fits between the ones next to it.
   14, 56, 75, 99

Check. Read the list again. Each number is bigger than the one before.

Watch out. Compare tens first. 52 comes before 61 because 5 tens is less than 6 tens.

Method. Find the least number by comparing the tens first.

1. Look at the tens. The numbers with the most tens are the greatest.
   3, 8, 6
2. Check the ones if two numbers have the same tens. The ones decide between them.
   34, 87, 65
3. Choose the least. It is the smallest of the numbers in the list.
   34

Check. Put the others in order to check: 34 is the least of them all.

Watch out. The number with the largest ones digit is not always the greatest.

Method. Compare the tens first. If the tens are the same, compare the ones.

1. Compare the tens digits. The tens digit is worth the most.
   9 and 6
2. Tens are different, so the tens decide. 9 tens is more than 6 tens.
   9 tens and 6 tens
3. Write the sign. 92 is greater than 62.
   >

Check. 92 > 62 is true.

Watch out. Compare tens first. 61 is greater than 58, because 6 tens is more than 5 tens.

Method. Put the numbers in order, smallest to largest. Find the first one and then the next.

1. Look at the tens of each number. The numbers with fewer tens are smaller.
   29: 2 tens, 69: 6 tens, 85: 8 tens, 80: 8 tens
2. Find the first number in the order. It is the smallest, or the largest if we go the other way.
   29
3. Write the numbers in order. Check that each one fits between the ones next to it.
   29, 69, 80, 85

Check. Read the list again. Each number is bigger than the one before.

Watch out. Compare tens first. 52 comes before 61 because 5 tens is less than 6 tens.

Method. Compare the tens first. If the tens are the same, compare the ones.

1. Compare the tens digits. The tens digit is worth the most.
   9 and 7
2. Tens are different, so the tens decide. 9 tens is more than 7 tens.
   9 tens and 7 tens
3. Write the sign. 99 is greater than 71.
   >

Check. 99 > 71 is true.

Watch out. Compare tens first. 61 is greater than 58, because 6 tens is more than 5 tens.