5th Grade Adding and Subtracting Decimals Test Solutions and Scoring (PDF)

(a) 7 tenths + 5 tenths = 12 tenths. 1.2

(b) \(6.35+2.40=8.75\). 8.75

Scoring: 1 point for each correct sum.

Hundredths: 6 + 8 = 14, write 4, regroup 1. Tenths: 7 + 5 + 1 = 13, write 3, regroup 1. Ones: 8 + 9 + 1 = 18, write 8, regroup 1. Tens: 3 + 1 + 1 = 5.

Answer: 58.34

Scoring: 1 point for correct alignment and regrouping, 1 point for the correct sum.

(a) \(5.2-1.8=3.4\). 3.4

(b) \(9.00-4.57=4.43\). 4.43

Scoring: 1 point for each correct difference.

\(63.04-27=36.04\), then \(36.04-0.89=35.15\).

Check: \(35.15+27.89=63.04\).

Answer: 35.15

Scoring: 1 point for correct regrouping, 1 point for the correct difference.

Estimate: \(48+22=70\).

Exact: \(47.80+22.30=70.10\).

Answer: estimate 70, exact 70.1

Scoring: 1 point for the estimate, 1 point for the exact sum.

Ethan lined up the right-most digits instead of the decimal points, so he added tenths to hundredths. Line up the points: \(3.60+2.45=6.05\).

Answer: 6.05

Scoring: 1 point for the explanation (decimal points not lined up), 1 point for 6.05.

(a) \(6.75+2.49=9.24\). \(9.24+1.35=10.59\). \(\$10.59\)

(b) \(20.00-10.59=9.41\). \(\$9.41\)

Scoring: (a) 1 point for adding the first two prices correctly, 1 point for the total. (b) 1 point.

(a) \(3.40+2.85=6.25\). 6.25 miles

(b) \(8.00-6.25=1.75\). 1.75 miles

Check: \(6.25+1.75=8.00\).

Scoring: (a) 1 point. (b) 1 point for setting up \(8-6.25\), 1 point for the answer.

Gray: 0.36. Light gray: 0.29.

\(0.36+0.29=0.65\).

Answer: 0.65

Scoring: 1 point for the decimals 0.36 and 0.29, 1 point for 0.65.