5.1-Unit 2: Adding and Subtracting Decimals
In this unit, students will review the first two standards of their new decimal unit, 5NBT1 and 5NBT3a (place value and reading/writing/expanding decimals respectively). 5NBT1 is a partial review from the previous unit, but we will also be focusing on the 'decimal side' of our place value chart (up to the thousandths) ,not just our 'whole number side'. We will also be introduced to two new standards, 5NBT3b (comparing decimals to the thousandths place) as well as 5NBT4 (rounding decimals). There will be multiple strategies taught to practice the skills, with one of our most important tools being our base 10 blocks that we will now view as decimals instead of wholes. Finally, students will move to the final standard of the unit, 5.NBT.7, which focuses on operations with decimals. Please note that this standard covers all four operations (add, subtract, multiply, and divide) but Unit 2 only goes over addition and subtraction (multiplication and division will be addressed in Unit 3). When focusing on both addition and subtraction; students will learn to "line up the dot, and give it all you've got!". We will also be tackling addition and subtraction of decimals in word problems as well throughout this unit.
5.1 Standards for Unit 2:
5.NBT.1 - Recognize that in a multi-digit number, a digit in one place represents 10 times as much as it represents in the place to its right and 1/10 of what it represents in the place to its left.
5.NBT.3a - Read, write, and compare decimals to thousandths.
a. Read and write decimals to thousandths using base-ten numerals, number names, and expanded form, e.g., 347.392 = 3 × 100 + 4 × 10 + 7 × 1 + 3 × (1/10) + 9 × (1/100) + 2 × (1/1000).
5.NBT.3b - Compare two decimals to thousandths based on meanings of the digits in each place, using >, =,
and < symbols to record the results of comparisons.
5.NBT.4 - Use place value understanding to round decimals up to the hundredths place.
5.NBT.7 Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and
subtraction; relate the strategy to a written method and explain the reasoning used.