Solve Addition Equation: Finding Missing Number in 46 + □ = 55

To solve the addition problem $46 + \Box = 55$ with two jumps on the number line, follow these steps:

• First, identify the starting point, which is 46, and the desired endpoint, which is 55.
• Make the first jump from 46 to the next higher round number. This number is 50 because it is the nearest round number greater than 46.
• The length of this first jump is calculated by subtracting 46 from 50, which is $50 - 46 = 4$.
• From 50, make the second jump to reach 55.
• The length of this second jump is obtained by subtracting 50 from 55, which is $55 - 50 = 5$.
• Add the lengths of both jumps to find the missing number $\Box$:
$\Box = 4 + 5 = 9$

Therefore, the solution to the problem is the missing number $\Box$, which is $9$.