帮我以视频的形式解答这个数学题---Question Stem:
丽莎阿姨准备了50包椰浆饭, 卖了一些椰浆饭后, 还剩下 22包。
以 N 为未知数, 写出算式。
Extracted Text:
丽莎阿姨准备了50包椰浆饭, 卖了一些椰浆饭后, 还剩下 22包。
以 N 为未知数, 写出算式。
Interpretation:
Aunt Lisa prepared 50 packets of nasi lemak, after selling some, there were 22 packets left. Using N as the unknown, write the calculation formula.
Variables and Numbers:
Initial packets: 50
Remaining packets: 22
Number of packets sold: N (unknown)
Mathematical Relationship (implied):
Initial packets - Packets sold = Remaining packets
50 - N = 22
Alternatively, to find the unknown N (packets sold):
Packets sold = Initial packets - Remaining packets
N = 50 - 22
Or, if N represents the remaining packets after selling some amount (let's call the sold amount 'S'):
50 - S = N, where S is unknown. But the problem specifically asks to use N as the unknown representing the *sold* amount.
So, the primary equation based on the wording "卖了一些椰浆饭后, 还剩下 22包" and using N for "卖了一些" (the amount sold) is:
50 - N = 22
Another way to express this using N as the unknown is:
N + 22 = 50
or
50 - 22 = N
Given the instruction "写出算式" (write the calculation formula), multiple valid equations using N are possible depending on how N is incorporated. However, the most direct representation of "50 minus the sold amount equals 22" is 50 - N = 22. If the task is to write a formula to find N, then N = 50 - 22 or N + 22 = 50 are possibilities. The phrase "以N为未知数，写出算式" usually means writing an equation where N is the unknown.
Possible interpretations for the "算式" (calculation formula):
1. The equation representing the situation: 50 - N = 22
2. The equation to solve for N: N = 50 - 22
3. An equation where N is the variable being added/subtracted: N + 22 = 50 (less likely as N represents the amount sold)
Assuming N represents the amount sold, the most direct "算式" is 50 - N = 22.
Let's present the extracted text clearly.
Extracted Content:
丽莎阿姨准备了50包椰浆饭, 卖了一些椰浆饭后, 还剩下 22包。
以 N 为未知数, 写出算式。
Breakdown:
- Initial amount: 50包椰浆饭 (50 packets of nasi lemak)
- Amount sold: 一些椰浆饭 (some nasi lemak) - represented by N
- Amount remaining: 22包 (22 packets)
- Instruction: 以 N 为未知数, 写出算式 (Using N as the unknown, write the calculation formula)
Mathematical Representation based on text:
50 - N = 22