# Math Notes

5882 + 23532 = 5882353

# The Haberdasher’s Problem

Can you make three cuts in a square of cloth and rearrange the pieces to form an equilateral triangle?

# Fallow and Fertile

Albrecht Dürer’s Melencolia I might brood about thwarted creativity, but it contains one of the most brilliant magic squares in all of European art.

You can reach the sum of 34 by adding the numbers in any row, column, diagonal, or quadrant; the four center squares; the four corner squares; the four numbers clockwise from the corners; or the four counterclockwise.

As a bonus, the two numbers in the middle of the bottom row give the date of the engraving: 1514.

# Math Notes

0588235294117647 × 1 = 0588235294117647
0588235294117647 × 8 = 4705882352941176
0588235294117647 × 3 = 1764705882352941
0588235294117647 × 2 = 1176470588235294
0588235294117647 × 7 = 4117647058823529
0588235294117647 × 5 = 2941176470588235
0588235294117647 × 9 = 5294117647058823
0588235294117647 × 6 = 3529411764705882
0588235294117647 × 4 = 2352941176470588

# Overtime

Victoria Crater, on Mars. The black dot on the rim, at about the 10 o’clock position, is the Mars rover Opportunity. Expected to fail after 90 days, it has been exploring faithfully for more than three years.

# Not So Fast

n2n + 41 produces prime numbers for all integers from 0 to 40 — but it fails when n equals 41.

# Suburban Physics

You’re driving a car. The windows are closed. In the back seat is a kid holding a helium balloon.

You turn right. You and the kid sway to the left. What does the balloon do?

25 × 92 = 2592

# Math Notes

13 + 53 + 33 = 153

# The Beverly Clock

In the foyer of the Department of Physics at New Zealand’s University of Otago is a clock that has been running continuously since 1864. The “Beverly Clock” is driven by variations in atmospheric pressure and by daily temperature variations, so it never needs winding.