Solve the Equation: Finding the Missing Number in 81 + __ = 98

To solve the problem $81 + \Box = 98$ using two jumps along a number line, follow these steps:

• Step 1: Start at 81 on the number line.
• Step 2: Make the first jump from 81 to the next convenient round number: 90.
• Step 3: Calculate the increase from 81 to 90: $90 - 81 = 9$.
• Step 4: Make the second jump from 90 to 98.
• Step 5: Calculate the increase from 90 to 98: $98 - 90 = 8$.
• Step 6: Add both jumps to determine the total required increment: $9 + 8 = 17$.

The total increment needed to go from 81 to 98 using two jumps is $17$.

Therefore, the solution to the problem is $\Box = 17$.