### Standard 5: Estimation

In grades K-4, the curriculum should include estimation so students can:
• Explore estimation strategies
• Recognize when an estimate is appropriate
•
Benchmarks 9A (The Mathematical World: Numbers)
Grades K-2, page 211
It is possible (and often useful) to estimate quantities without knowing them exactly.

Benchmarks 9D (The Mathematical World: Uncertainty)
Grades 3-5, page 227
Statistical predictions (as for rainy days, accidents) are typically better for what proportion of a group will experience something than for which members of the group will experience it and better for how often something will happen than for exactly when.

• Determine the reasonableness of an estimate
•
Benchmarks 12B (Habits of Mind: Computation and Estimation)
Grades K-2, page 290
Make quantitative estimates of familiar lengths, weights, time intervals and check them by measurements.

Benchmarks 12B (Habits of Mind: Computation and Estimation)
Grades K-2, page 290
Readily give the sums and differences of single-digit numbers in familiar contexts where the operation makes sense and they can judge the reasonableness of the answer.

• Apply estimation in working with quantities, measurement, computation, and problem solving
•
Benchmarks 12B (Habits of Mind: Computation and Estimation)
Grades K-2, page 290
Give rough estimates of numerical answers to problems before doing them formally.

Benchmarks 12B (Habits of Mind: Computation and Estimation)
Grades K-2, page 290
Judge whether measurements and computations of quantities such as length, area, volume, weight, or time are reasonable in a familiar context by comparing them to typical values.