Description
Build fluent within-20 skills with clean, kid-friendly input–output function tables. Students practice addition & subtraction using three progressive sections—Follow the Rule, Find the Rule, and Missing Cell Mix—with a dedicated Equation box so learners can “show their work.” Perfect for whole group, centers, small group, sub plans, homework, or quick checks. B&W, ink-friendly, no prep.
What’s Inside
- 18 student pages (Within 20) organized into 3 sections
- Follow the Rule (P1–P6): +10, +5, +9; −1/−2, −5, −9 (near-ten)
- Find the Rule (P7–P12): infer the rule from input→output; includes mixed/per-row and missing inputs
- Missing Cell Mix (P13–P18): given rule→missing output, given rule→missing input, missing rule, mixed & review
- Consistent layout: each page = 2 tables × 4 rows with Input | Equation | Output (or Input | Output | Rule | Equation for Find-the-Rule)
- Answer Keys for every page for quick grading
- Teacher tips on near-ten strategies (+9 = +10 − 1, −9 = −10 + 1)
- US Letter • PDF • B&W (print-and-go)
Skills & Focus
- Add/Subtract within 20 using mental strategies (±10, ±5, ±1/±2, near-ten ±9)
- Pattern recognition in function tables
- Explaining thinking with an Equation box (show your work)
How to Use
- Model the first example row, then have students apply the same rule to complete the table (P7–P10, P12).
- Use Missing Cell Mix for spiral review, stations, or exit tickets.
- Pair with number lines (0–20) for near-ten problems.
Standards Alignment (K–2)
- 1.OA.C.6 (Add/Sub within 20; fluency via strategies)
- 2.OA.B.2 (Mental strategies; fact fluency)
- Extends foundations toward 2.NBT.B.5 when ready
Printing & Prep
- B&W, ink-friendly design
- 1 page = 2 tables × 4 rows (large writing space for primary students)
- Clear Rule banner/box on each table (where applicable)
Keywords: input output tables, function tables, function machines, add and subtract within 20, mental math, near ten, plus 10 minus 10, worksheets, printable, answer key, math centers, show your work, equation box, first grade math, second grade math, grade 1, grade 2, special education, intervention
Input–Output Function Tables | Add & Subtract Within 20 Worksheets + Answer Keys
Highlights
Description
Build fluent within-20 skills with clean, kid-friendly input–output function tables. Students practice addition & subtraction using three progressive sections—Follow the Rule, Find the Rule, and Missing Cell Mix—with a dedicated Equation box so learners can “show their work.” Perfect for whole group, centers, small group, sub plans, homework, or quick checks. B&W, ink-friendly, no prep.
What’s Inside
- 18 student pages (Within 20) organized into 3 sections
- Follow the Rule (P1–P6): +10, +5, +9; −1/−2, −5, −9 (near-ten)
- Find the Rule (P7–P12): infer the rule from input→output; includes mixed/per-row and missing inputs
- Missing Cell Mix (P13–P18): given rule→missing output, given rule→missing input, missing rule, mixed & review
- Consistent layout: each page = 2 tables × 4 rows with Input | Equation | Output (or Input | Output | Rule | Equation for Find-the-Rule)
- Answer Keys for every page for quick grading
- Teacher tips on near-ten strategies (+9 = +10 − 1, −9 = −10 + 1)
- US Letter • PDF • B&W (print-and-go)
Skills & Focus
- Add/Subtract within 20 using mental strategies (±10, ±5, ±1/±2, near-ten ±9)
- Pattern recognition in function tables
- Explaining thinking with an Equation box (show your work)
How to Use
- Model the first example row, then have students apply the same rule to complete the table (P7–P10, P12).
- Use Missing Cell Mix for spiral review, stations, or exit tickets.
- Pair with number lines (0–20) for near-ten problems.
Standards Alignment (K–2)
- 1.OA.C.6 (Add/Sub within 20; fluency via strategies)
- 2.OA.B.2 (Mental strategies; fact fluency)
- Extends foundations toward 2.NBT.B.5 when ready
Printing & Prep
- B&W, ink-friendly design
- 1 page = 2 tables × 4 rows (large writing space for primary students)
- Clear Rule banner/box on each table (where applicable)
Keywords: input output tables, function tables, function machines, add and subtract within 20, mental math, near ten, plus 10 minus 10, worksheets, printable, answer key, math centers, show your work, equation box, first grade math, second grade math, grade 1, grade 2, special education, intervention
