Question

replace the values for c to see which gives you a sum of 7.7.
\\(\

$$\begin{array}{r}\\ 1.5 \\\\ +\\ 3.6 \\\\ \\hline \\square.\\square\\end{array}$$

\\) \\(\

$$\begin{array}{r}\\ 1.5 \\\\ +\\ 4.1 \\\\ \\hline \\square.\\square\\end{array}$$

\\) \\(\

$$\begin{array}{r}\\ 1.5 \\\\ +\\ 6.2 \\\\ \\hline \\square.\\square\\end{array}$$

\\) \\(\

$$\begin{array}{r}\\ 1.5 \\\\ +\\ 5.8 \\\\ \\hline \\square.\\square\\end{array}$$

\\)

Explanation:

Step1: Calculate first sum

$1.5 + 3.6 = 5.1$

Step2: Calculate second sum

$1.5 + 4.1 = 5.6$

Step3: Calculate third sum

$1.5 + 6.2 = 7.7$

Step4: Calculate fourth sum

$1.5 + 5.8 = 7.3$

Answer:

The pair $1.5 + 6.2$ gives a sum of 7.7.
Completed sums:
$1.5 + 3.6 = 5.1$
$1.5 + 4.1 = 5.6$
$1.5 + 6.2 = 7.7$
$1.5 + 5.8 = 7.3$