#### Math - 2018-19

# 4.6 - Decimal Computation

**The student will**

a)
**add** and
**subtract** decimals;* and

b)
**solve**
single-step and multistep practical problems involving addition and subtraction
with decimals.

**On the state assessment, items measuring this objective are
assessed without the use of a calculator.*

*Adopted: 2016*

### BIG IDEAS

We use measurement every day.We look at the temperature to see what we should wear to school. We measure ourselves to see if we are growing. What other things can you think of that we measure?

We often use measurements of mass in Science to see how heavy an object is. We also measure liquids for experiments.

- Engineers use measurements daily when they are designing things such as bridges.

### UNDERSTANDING THE STANDARD

- Addition and subtraction of decimals may be explored, using a variety of models (e.g., 10-by-10 grids, number lines, money)
- The problem-solving
process is enhanced when students create and solve their own practical problems
and model problems using manipulatives and drawings.
- In problem solving, emphasis should be placed on thinking and reasoning
rather than on key words. Focusing on key words such as
*in all, altogether, difference,*etc*.*encourages students to perform a particular operation rather than make sense of the context of the problem. It prepares students to solve a very limited set of problems and often leads to incorrect solutions. - The least number of steps
necessary to solve a single-step problem is one.

### ESSENTIALS

**The student will use problem solving, mathematical communication, mathematical reasoning, connections, and representations to**

- Estimate
sums and differences of decimals. (a)
- Add and
subtract decimals through thousandths, using concrete materials, pictorial
representations, and paper and pencil. (a)
- Solve single-step and
multistep practical problems that involve adding and subtracting with decimals
through thousandths. (b)

### KEY VOCABULARY

*Updated: Aug 22, 2018*