Question

How can these models be used to find the sum 1.8 + 1.56?

Enter your answers in the boxes.

The models show a total of 2 wholes,
tenths, and
hundredths. After regrouping 10 tenths into 1 whole, there are
wholes,
tenths, and
hundredths. Therefore, the sum of the numbers is
.
First row. One large square divided into a 10 by 10 grid of 100 small squares. Eight columns, each divided into 10 small squares. Second row. One large square divided into a 10 by 10 grid of 100 small squares. Five columns, each divided into 10 small squares. Six small squares.

Answer 1

The sum of 1.8 and 1.56 is 3.36 according to the model

Sum of decimals

Given the expression 1.8 + 1.56

Using the partial sum method

1.8 + 1.56 = (1.0 + 0.8) + (1.0+0.56)

Regroup as whole and decimal number

1.8 + 1.56 = (1.0 + 1.0) + (0.8 +0.56)

1.8 + 1.56 = 2.0 + 1.36

1.8 + 1.56 = 3.36

Hence the sum of 1.8 and 1.56 is 3.36 according to the model