Math Games

Grade 7 - Number

Standard 7.N.2 - Practice estimating sums, differences, and products with decimals.

Included Skills:

Expand and demonstrate understanding of the addition, subtraction, multiplication, and division of decimals to greater numbers of decimal places, and the order of operations.
• Provide a justification for the placement of a decimal in a sum or difference of decimals up to thousandths (e.g., for 4.5 + 0.73 + 256.458, think 4 + 256 so the sum is greater than 260; thus, the decimal will be placed so that the sum is in the hundreds).
• Provide a justification for the placement of a decimal in a product (e.g., for $12.33 × 2.4, think $12 × 2, so the product is greater than $24; thus, the decimal in the final product would be placed so that the answer is in the tens).
• Provide a justification for the placement of a decimal in a quotient (e.g., for 51.50 m ÷ 2.1, think 50 m ÷ 2 so the quotient is approximately 25 m; thus, the final answer will be in the tens). (Note: If the divisor has more than one digit, students should be allowed to use technology to determine the final answer.)
• Solve a problem involving the addition, or subtraction, of two or more decimal numbers.
• Solve a problem involving the multiplication or division of decimal numbers with 2-digit multipliers or 1-digit divisors (whole numbers or decimals) without the use of technology.
• Solve a problem involving the multiplication or division of decimal numbers with more than a 2-digit multiplier or 1-digit divisor (whole number or decimal), with the use of technology.
• Check the reasonableness of solutions using estimation.
• Solve a problem that involves operations on decimals (limited to thousandths) taking into consideration the order of operations.
• Explain by using examples why it is important to follow a specific order of operations when calculating with decimals and/or whole numbers.