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    Second Grade
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    Scoring guide · Weeks 7–12 · 35–40 min · 52 points

    Math Unit 2 Test: Addition & Subtraction Within 100

    Directions for the grown-up

    Give this test on a calm day, after the unit's last lesson. Sit with your child and read the directions for each part aloud. Read any item aloud if your child asks. Reading is not what this test checks. Do not time the test. The time given is only a guide, so you can plan. Take a short break between parts if your child is tired. Do not teach or hint during the test. If your child is stuck, say "Do your best, then we can move on." When you score, use the answer and the partial-credit notes for each part. Then add the points and find the level at the end. Your child may use the tools from the lessons: base-ten blocks or straw bundles, base-ten drawings, an open number line and a hundreds chart. Ask your child to do the Mental Math part without writing the problem out in columns.

    Part 1: Computation Fluency (20 points)

    Standards: 2.NBT.B.5, 2.NBT.B.6, 2.NBT.B.7

    1. 49 + 36 = ____Answer: 85 · 2 points
    2. 83 − 26 = ____Answer: 57 · 2 points
    3. 68 + 25 = ____Answer: 93 · 2 points
    4. 94 − 58 = ____Answer: 36 · 2 points
    5. 70 − 34 = ____Answer: 36 · 2 points
    6. 17 + 46 + 25 = ____Answer: 88 · 2 points
    7. 12 + 27 + 33 + 19 = ____Answer: 91 · 2 points
    8. 458 + 271 = ____Answer: 729 · 2 points
    9. 367 + 245 = ____Answer: 612 · 2 points
    10. 715 − 482 = ____Answer: 233 · 2 points

    Scoring: 2 points for each correct answer. 1 point if the strategy or drawing is right but there is one small slip (for example, a trade was forgotten or one digit is off).

    Reteach: Week 7, Week 8, Week 9Week 7 Days 1–3 (adding and subtracting within 100), Week 8 Days 1–3 (adding three or four two-digit numbers) and Week 9 Days 1–3 (adding and subtracting within 1000 with trades).

    Part 2: Mental Math (±10, ±100) (12 points)

    Standards: 2.NBT.B.8

    1. 10 more than 436 is ____. 10 less than 436 is ____.Answer: 446; 426 · 2 points
    2. 100 more than 258 is ____. 100 less than 258 is ____.Answer: 358; 158 · 2 points
    3. 10 more than 695 is ____. 10 less than 703 is ____.Answer: 705; 693 · 2 points
    4. 100 less than 180 is ____. 100 more than 900 is ____.Answer: 80; 1000 · 2 points
    5. 527 + ____ = 627 850 − ____ = 840Answer: 100; 10 · 2 points
    6. A school library has 342 books. It gets 100 more books, then 10 more books. How many books does it have now?Answer: 452 books (342 + 100 = 442, 442 + 10 = 452) · 2 points

    Scoring: Items 1–5: 1 point for each blank. Item 6: 2 points for 452; 1 point if one step is right (442 or 352).

    Reteach: Week 10Week 10 Days 1–4 (10 and 100 more and less, crossing a hundred, and story problems).

    Part 3: Word Problems (12 points)

    Standards: 2.OA.A.1, 2.NBT.B.5, 2.NBT.B.6, 2.NBT.B.7

    1. Maya picked 38 apples. Her brother picked 49 apples. How many apples did they pick in all?Answer: 87 apples (38 + 49 = ?) · 3 points
    2. A farm had 83 chickens. Some were sold. Now 55 chickens are left. How many chickens were sold?Answer: 28 chickens (83 − ? = 55) · 3 points
    3. Tia read 23 pages on Monday, 42 pages on Tuesday and 15 pages on Wednesday. How many pages did she read?Answer: 80 pages (23 + 42 + 15 = ?) · 3 points
    4. A theater has 450 seats. 276 seats have people in them. How many seats are empty?Answer: 174 seats (450 − 276 = ?) · 3 points

    Scoring: For each problem: 1 point for a model or equation that fits the story, 1 point for the correct number, 1 point for a label word (apples, chickens, pages, seats). An equation such as 55 + ? = 83 also earns the model point.

    Reteach: Week 7, Week 8, Week 9, Week 12Week 7 Day 4, Week 8 Day 4, Week 9 Day 4 (word problems and checking with the opposite operation) and Week 12 Day 4.

    Part 4: Strategy Explanation (8 points)

    Standards: 2.NBT.B.9

    1. Solve 38 + 46 two different ways. You can use make a ten, an open number line, or tens and ones. Tell why both ways give the same answer.Answer: 4 points: two different correct strategies, both giving 84 (for example, 38 + 2 = 40, 40 + 44 = 84; and 30 + 40 = 70, 8 + 6 = 14, 70 + 14 = 84), plus a reason such as "both ways add the same tens and ones". 3 points: two correct strategies and a weak reason. 2 points: one correct strategy with 84. 1 point: 84 with no clear strategy. 0: no correct answer. · 4 points
    2. Ali solved 73 − 39 and got 46. What mistake did Ali make? Solve it the right way. Explain the trade with tens and ones.Answer: 4 points: says Ali did 9 − 3 instead of 3 − 9; solves 73 − 39 = 34; explains trading 1 ten for 10 ones (7 tens 3 ones becomes 6 tens 13 ones; 13 − 9 = 4, 6 tens − 3 tens = 3 tens). 3 points: 34 and a mostly clear explanation. 2 points: 34 with little explanation, or finds the mistake but does not solve correctly. 1 point: says 46 is wrong with no fix. 0: no correct part. · 4 points

    Scoring: Use the rubric in each answer. Drawings of tens and ones count as explanations.

    Reteach: Week 11Week 11 Days 1–4 (why make a ten, decomposing, number lines and trades work; checking a sample explanation).

    D/A/P/E point bands (out of 52)
    LevelPoints
    D · Developing0–25
    A · Approaching26–36
    P · Proficient37–46
    E · Exemplary47–52