Reteaching

Set A, pages 24-25

What is the number halfway between 800 and 900?

Use a number line.
Find the number that is the same distance from the beginning number and the ending number. The number that is halfway between 800 and 900 is 850.

Remember to check that your number is the same distance from the beginning number and the ending number on a number line.

Find the number halfway between each pair of numbers.
Question 1.
60 and 70 Question 2.
2,000 and 3,000 Question 3.
900 and 1,000

Question 4.
3,300 and 3,400

Question 5.
860 and 870

Set B, pages 26-28

Round 867 to the nearest hundred. On the number line, 867 is closer to 900 than to 800.
You can also use place value. Since 6 > 5, increase the digit in the hundreds place by one. Then change all the digits to the right to zero.
To the nearest hundred, 867 rounds to 900.

Remember to think of the halfway number when rounding.

Round to the nearest ten.
Question 1.
65

Question 2.
813

Question 3.
489

Question 4.
24

Question 5.
78

Question 6.
942

Round to the nearest hundred.
Question 7.
229

Question 8.
349

Question 9.
651

Question 10.
856

Question 11.
109

Question 12.
783

Set C, pages 30-31

Round 2,613 to the nearest thousand. You can use place value. • Find the digit in the rounding place. That digit is 2.
• If the next digit to the right is 5 or greater, increase the digit in the rounding place by 1. If the next digit is less than 5, keep the digit in the counding place as it is. Since 6 > 5, increase the 2 to 3.
• Change all the digits to the right of the rounding place to zero.
To the nearest thousand, 2,613 rounds to 3,000.

Remember to compare the correct digit to 5 to find if the digit in the rounding place should change.

Round to the nearest thousand.
Question 1.
3,817

Question 2.
6,495

Question 3.
8,562

Question 4.
1,709

Question 5.
2,500

Question 6.
7,248

Question 7.
5,692

Question 8.
3,178

Question 9.
9,714

Round to the nearest hundred.
Question 10.
2,136

Question 11.
5,624

Question 12.
4,449

Question 13.
7,751

Question 14.
6,275

Question 15.
8,941

Question 16.
4,307

Question 17.
9,768

Question 18.
3,549

Set D, pages 32-33

Follow these steps for using Try, Check, and Revise to solve problems.
Step 1: Think to make a reasonable first try.
Step 2: Check using information from the problem.
Step 3: Revise. Use your first try to make a reasonable second try. Check.
Step 4: Continue trying and checking until you find the correct answer.

Remember to check each try.

Use Try, Check, and Revise to solve.
Question 1.
Mark and Tony have 32 markers. Mark has 2 more markers than Tony. How many markers does each boy have?