Number sense suite

Number sense routines for K–3

Every tool runs the same Flash → Wait → Ask → Reveal routine, with built-in prompts, research-based presets, and one-click projection mode. Free, login-free, no student data.

Flash Routines

Grades K–2

Subitizing Free

Instantly "see" small quantities as groups, not counts. Perceptual and conceptual subitizing on the Clements & Sarama trajectory.

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Grades 1–3

Fact Fluency Strategy Flash Free

Fluency as flexible strategy, not rote speed — every reveal shows the visual model behind doubles, make ten, and using ten.

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Grades K–3

Number Line Estimation Free

Number-line estimation both predicts and trains later achievement (Siegler & Booth). Estimate, mark, and reveal the true spot.

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Grades K–2

Quantity Compare & Missing Number Free

Magnitude comparison and sequence sense — two early-numeracy screener task types the class can reason through without counting all.

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Grades 1–3

Place Value Quick Images Free

Flashed base-ten arrangements build the tens-and-ones structure of number — canonical images bonded into place value.

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Grades K–2

Rekenrek Flash Free

The 5- and 10-structure made visible. Flash bead configurations and discuss how the red beads help you see the number.

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Choral Counting

Grades K–3

Choral Counting Free

Count by 1s, 5s, or 10s from any start value, forward or backward — the track accumulates so the class sees the pattern build, row by row.

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Grades 2–3

Choral Money Counting Free

Count by pennies, nickels, dimes, or quarters from any start value — same accumulating track, one coin denomination at a time (CCSS 2.MD.8).

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Grades 3–5

Choral Decimal Counting Free

Count by tenths or hundredths, forward or backward, sailing right past one whole (0.9 to 1.0) — directly countering the "longer is larger" decimal misconception.

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Grades 2–3

Choral Time Counting Free

Count by seconds or minutes on a real clock face, watching the seconds roll past 59 into the next minute — a base-60 system riding inside a routine that otherwise counts by ones (CCSS 2.MD.7, 3.MD.1).

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Looking for fractions?

The DotSense Fraction Routines are a separate suite for grades 1–5, built to prevent and dislodge whole-number bias.

Explore fractions →