Which models represent the sum?

Question

1.2 + 0.3

Select each correct answer.

Responses

Two 10 by 10 grids of 100 squares. All 10 columns of first square and 2 columns of the second square shaded one color. Three columns of the second square shaded a different color.
Image with alt text: Two 10 by 10 grids of 100 squares. All 10 columns of first square and 2 columns of the second square shaded one color. Three columns of the second square shaded a different color.

Large square divided into a 10 by 10 grid of 100 small squares. Two columns, each divided into 10 small squares. Plus sign. Three columns, each divided into 10 small squares.
Image with alt text: Large square divided into a 10 by 10 grid of 100 small squares. Two columns, each divided into 10 small squares. Plus sign. Three columns, each divided into 10 small squares.

Ten by 10 grid of 100 squares. The first column and 2 squares of the second column are shaded one color. The next three columns are shaded another color.
Image with alt text: Ten by 10 grid of 100 squares. The first column and 2 squares of the second column are shaded one color. The next three columns are shaded another color.

Number line from 0 to 4 by tenths. An arrow shows a jump starting at 0 and ending 2 marks past 1. Another arrow shows a jump starting at 2 marks past 1 and ending at 5 marks past 1.
Image with alt text: Number line from 0 to 4 by tenths. An arrow shows a jump starting at 0 and ending 2 marks past 1. Another arrow shows a jump starting at 2 marks past 1 and ending at 5 marks past 1.

One column, divided into 10 small squares. Two small squares. Plus sign. Three columns, each divided into 10 small squares.
Image with alt text: One column, divided into 10 small squares. Two small squares. Plus sign. Three columns, each divided into 10 small squares.

Answer 1

To determine which models accurately represent the sum of 1.2 + 0.3, we need to analyze how each choice visualizes the addition of these two numbers.

1. 1.2 can be represented as 1 whole (10 tenths) and 2 tenths (2/10).
2. 0.3 can be represented as 3 tenths (3/10).
3. The total for 1.2 + 0.3 = 1.5 (or 1 whole and 5 tenths).

Now, let's evaluate each model closely:

1. First Option: Two 10 by 10 grids, shading 10 columns in one and 2 columns in the other, with 3 columns shaded differently. This doesn't clearly illustrate 1.2 + 0.3.

2. Second Option: A large grid with 2 columns for the first number and 3 columns for the second number visually indicates the addition. This could be interpreted as showing 1.2 and 0.3, making it a suitable model.

3. Third Option: One column and 2 small squares shaded one color, followed by 3 additional columns shaded a different color. This visual representation does not accurately convey the decimal values.

4. Fourth Option: A number line showing jumps from 0 to 1.2 and then from 1.2 to 1.5 (jump from 2 marks past 1 to 5 marks past 1). This effectively depicts the addition of 1.2 + 0.3.

5. Fifth Option: One column divided into 10 small squares and additional squares next to 3 columns. This setup does not accurately correlate to the values we are adding.

Thus, the options that correctly represent the sum of 1.2 + 0.3 are:

• The Second Option (grid illustrating parts of 1.2 and 0.3).
• The Fourth Option (number line illustrating the addition).

Therefore, the responses that correctly represent the sum are the Second Option and the Fourth Option.