Math Drill Pages

Estimating Products Worksheet

This 4th grade sheet has 18 multiplication estimation problems. Students round, write the rounded numbers, then multiply. Part A rounds 2-digit numbers to the nearest 10 and Part B rounds 3-digit numbers to the nearest 100, each times a 1-digit number; Part C rounds both 2-digit factors to the nearest 10.

Grade
Grade 4
Problems
18
Time
About 15 minutes
Standard
4.NBT.A.3, 4.OA.A.3
Download PDF (US Letter) Download PDF (A4)

Two pages: the worksheet, then the answer key. No sign-up needed.

Worksheet preview

Part A: 2-digit × 1-digit Round the 2-digit number to the nearest 10. Then multiply.

  1. 38×3≈40×3=120
  2. 23×8≈20×8=160
  3. 94×4≈90×4=360
  4. 87×4≈90×4=360
  5. 38×9≈40×9=360
  6. 39×5≈40×5=200

Part B: 3-digit × 1-digit Round the 3-digit number to the nearest 100. Then multiply.

  1. 603×6≈600×6=3,600
  2. 788×9≈800×9=7,200
  3. 762×7≈800×7=5,600
  4. 123×5≈100×5=500
  5. 226×5≈200×5=1,000
  6. 501×9≈500×9=4,500

Part C: 2-digit × 2-digit Round both numbers to the nearest 10. Then multiply.

  1. 41×47≈40×50=2,000
  2. 41×56≈40×60=2,400
  3. 59×18≈60×20=1,200
  4. 81×33≈80×30=2,400
  5. 49×34≈50×30=1,500
  6. 72×91≈70×90=6,300

Tips for teachers and parents

  • Round first, then multiply. Writing the rounded numbers in the blanks keeps the two steps apart: 38 × 3 becomes 40 × 3 = 120.
  • The rounded problems are multiples of 10 and 100, so students can solve them with a basic fact and zeros.
  • After each estimate, ask whether the exact answer is more or less. 38 was rounded up, so 38 × 3 is a little less than 120.
  • Use rounding to estimate before every long multiplication problem; an exact answer far from the estimate needs another look.

Common mistakes

  • Multiplying first and rounding the answer. The point of estimating is to make the multiplication easy.
  • Rounding a 3-digit number to the nearest 10 in Part B, which makes the problem hard again. Part B rounds to the nearest 100.

What to practice next

Estimate, then work out the exact answers on the 2-digit by 2-digit multiplication worksheet and compare.

Frequently asked questions

How do you estimate a product?

Round each factor, then multiply the rounded numbers. 41 × 56 is about 40 × 60 = 2,400.

What grade learns estimating products?

Grade 4. Students round multi-digit numbers (4.NBT.A.3) and use estimation to check whether answers are reasonable (4.OA.A.3).

Is there an answer key?

Yes, page 2 of the PDF shows the rounded numbers and the estimate for all 18 problems.