Math Games

Grade 5 - Number

Standard 5.N.11 - Solve addition and subtraction sentences with decimals.

Included Skills:

Demonstrate an understanding of addition and subtraction of decimals (to thousandths), concretely, pictorially, and symbolically, by
• using personal strategies
• using the standard algorithms
• using estimation
• solving problems

• Estimate a sum or difference using front-end estimation (e.g., for 6.3 + 0.25 + 306.158, think 6 + 306, so the sum is greater than 312) and place the decimal in the appropriate place.
• Correct errors of decimal point placements in sums and differences without using paper and pencil.
• Explain why keeping track of place value positions is important when adding and subtracting decimals.
• Predict sums and differences of decimals using estimation strategies.
• Solve a problem that involves addition and subtraction of decimals, to thousandths.
• Model and explain the relationship that exists between an algorithm, place value, and number properties.
• Determine the sum and difference using the standard algorithms of vertical addition and subtraction. (Numbers are arranged vertically with corresponding place value digits aligned.)
• Refine personal strategies, such as mental math, to increase efficiency when appropriate (e.g., 3.36 + 9.65 think, 0.35 + 0.65 = 1.00, therefore, 0.36 + 0.65 = 1.01 and 3 + 9 = 12 for a total of 13.01)