19 × 12 + 19 = 19 × (12 + ____)
1
Goal: Make the left side look like \(19\times(12+\_\_)\).
Step 1: Notice both parts have a 19: \(19\times12\) and \(19\).
Step 2: Write the plain \(19\) as a multiplication: \(19 = 19\times1\).
Step 3: Replace it on the left side:
\(19\times12 + 19\;=\;19\times12 + 19\times1\)
Step 4: Take out the common factor \(19\) (factorisation):
\(19\times12 + 19\times1\;=\;19\times(12 + 1)\)
Step 5: Now it matches \(19\times(12+\_\_)\), so the blank is \(1\).