Estimation and Rounding — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. Grade 4 estimate: 89 + 14 to the nearest 10 is about 100.
Rounded to tens, 90 + 10 = 100, a close estimate of 103.
2. Grade 4 estimate: 248 + 351 to the nearest 100 is about 600.
Rounded to hundreds, 200 + 400 = 600, near the actual 599.
3. Grade 4 estimate: 612 - 289 to the nearest 100 is about 300.
Rounded to hundreds, 600 - 300 = 300, near the actual 323.
4. Grade 4: 8,742 rounded to the nearest 1,000 is 9000.
Since 7 is 5 or more, 8,742 rounds up to 9,000.
5. Grade 4 estimate: 4,213 + 2,876 to nearest 1,000 is about 7000.
Rounded to thousands, 4,000 + 3,000 = 7,000, near the actual 7,089.
6. Grade 4: 3,500 rounded to the nearest 1,000 is 4000.
The 5-or-more rule rounds 3,500 up to 4,000.
7. Grade 4 estimate: 76 - 23 to the nearest 10 is about 60.
Rounded to tens, 80 - 20 = 60, near the actual 53.
8. Grade 4 estimate: 489 + 112 to the nearest 100 is about 600.
Rounded to hundreds, 500 + 100 = 600, near the actual 601.
9. In Grade 4, 6,051 rounded to the nearest 1,000 is 6000.
Since 0 is less than 5, 6,051 rounds down to 6,000.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Grade 4 estimate: 38 + 41 to nearest 10
→ 80
80
Grade 4 estimate: 712 - 198 to nearest 100
→ 500
500
Grade 4: 5,832 rounded to nearest 1,000
→ 6000
6000
Grade 4 estimate: 2,150 + 1,840 to nearest 1,000
→ 4000
4000
38 + 41 rounds to 40 + 40 = 80; 712 - 198 rounds to 700 - 200 = 500; 5,832 rounds to 6,000; 2,150 + 1,840 rounds to 2,000 + 2,000 = 4,000.