To solve the equation [tex]\( 1 + \square = 2 \)[/tex], we need to find the integer that, when added to 1, results in 2.
Here are the steps to find the missing integer:
1. Start with the equation:
[tex]\[
1 + \square = 2
\][/tex]
2. To isolate the missing integer (let's call it [tex]\( x \)[/tex]), subtract 1 from both sides of the equation:
[tex]\[
1 + x - 1 = 2 - 1
\][/tex]
3. Simplify both sides of the equation:
[tex]\[
x = 1
\][/tex]
Hence, the integer that makes the addition sentence [tex]\( 1 + \square = 2 \)[/tex] true is [tex]\( 1 \)[/tex].
The final answer is:
[tex]\[
\boxed{1}
\][/tex]
