Question

在这个数字阵列中，哪个数在 $142$ 的正上方？

$\begin{array}{ccccccccc} & & & & 1 & & & & \\ & & & 2 & 3 & 4 & & & \\ & & 5 & 6 & 7 & 8 & 9 & & \\ & 10 & 11 & 12 & \cdots & & & & \end{array}$

What number is directly above $142$ in this array of numbers?

$\begin{array}{ccccccccc} & & & & 1 & & & & \\ & & & 2 & 3 & 4 & & & \\ & & 5 & 6 & 7 & 8 & 9 & & \\ & 10 & 11 & 12 & \cdots & & & & \end{array}$

$99$

$119$

$120$

$121$

$122$

每一行都以一个完全平方数结尾，所以含 $142$ 的那一行以 $144 = 12^2$ 结尾，上一行以 $121 = 11^2$ 结尾。

因为各行右端对齐， $121$ 在 $143$ 的正上方，所以 $120$ 在 $142$ 的正上方。

所以正确答案是 C。

Each row ends at a perfect square, so the row containing $142$ ends at $144 = 12^2,$ and the row above it ends at $121 = 11^2.$

Since the rows are aligned at their right edges, $121$ sits directly above $143,$ and therefore $120$ sits directly above $142.$

Thus, the correct answer is C .