Math in the real world

Grade 6

You see that towering scale, front and center?

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That’s our not-so-subtle way of saying that one of the big ideas is balance!

On the left side, grains of salt are being measured as part of the trans-Saharan salt trade. It’s only appropriate that the man measuring out the salt is Omar Khayyam, a Persian mathematician who made early connections between the studies of shapes and numbers. Meanwhile, over on the right side of the balance there’s an intense discussion about whether to solve for an unknown weight by subtracting or dividing—that is, sawing part of the scale in half!

Grade 7

How many shapes can you make with six friends and some string?

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Mathematician Thomas Storer is standing in the middle of that hexagon, determined to find out.

Meanwhile, mathematicians Blaise Pascal and Fermat are taking a chance with probability, Thales of Miletus is measuring angles in the sky, and someone from England’s Bletchley Park is breaking codes.

Grade 8

Ready for a ride down a slope?

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Be sure to keep all your hands and feet inside the vehicle—Unless you are friends with mathematician John Horton Conway, who is dancing up a storm with his frieze patterns on a sandy beach.

Elsewhere on the cover, Zhang Qiujian is close to figuring out where the line of a roller coaster line will intersect yet another line. Fortunately, a pair of students are on-hand to help (although they seem to have different ways of calculating the slope).

Algebra 1

What goes up must come down, but how?

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The arc of a ball through the air isn’t a line—it’s something else entirely. Elsewhere on the cover, you can find Katherine Johnson working on the orbital trajectory of a rocket about to launch, and a student measuring the growth of a bacterial colony. Both the rocket and the bacterial population really take off!