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Sometimes, it is in two parts – and 20% of the time, it is absent. [2] In other mammals, it is larger. In 1889, a Portuguese anatomist by the name of Macedo examined 215 brains, showing that male humans are approximately twice as likely to lack an interthalamic adhesion as are female humans.
An elephant's brain weighs just over 5 kg (11 lb), a bottlenose dolphin's 1.5 to 1.7 kg (3.3 to 3.7 lb), whereas a human brain is around 1.3 to 1.5 kg (2.9 to 3.3 lb). Brain size tends to vary according to body size. The relationship is not proportional, though: the brain-to-body mass ratio varies. The largest ratio found is in the shrew. [57]
Many mathematical problems have been stated but not yet solved. These problems come from many areas of mathematics, such as theoretical physics, computer science, algebra, analysis, combinatorics, algebraic, differential, discrete and Euclidean geometries, graph theory, group theory, model theory, number theory, set theory, Ramsey theory, dynamical systems, and partial differential equations.
Treeshrews hold about 10% of their body mass in their brain. [16] Generally speaking, the larger the animal, the smaller the brain-to-body mass ratio is. Thus, large whales have very small brains compared to their weight, and small rodents like mice have a relatively large brain, giving a brain-to-body mass ratio similar to humans. [4]
A typical sequence of secondary-school (grades 6 to 12) courses in mathematics reads: Pre-Algebra (7th or 8th grade), Algebra I, Geometry, Algebra II, Pre-calculus, and Calculus or Statistics. However, some students enroll in integrated programs [3] while many complete high school without passing Calculus or Statistics.
Many students work in groups to solve them and help get a better understanding of the material, [6] [7] but most professors require each student to hand in their own individual problem set. Some professors explicitly encourage collaboration, [ 5 ] [ 6 ] some allow it, and some explicitly disallow it [ 3 ] or consider it cheating.
The P versus NP problem, which remains open to this day, is also important for discrete mathematics, since its solution would potentially impact a large number of computationally difficult problems. [45] Discrete mathematics includes: [14] Combinatorics, the art of enumerating mathematical objects that satisfy some given constraints.
The adult human brain weighs on average about 1.2–1.4 kg (2.6–3.1 lb) which is about 2% of the total body weight, [2] [3] with a volume of around 1260 cm 3 in men and 1130 cm 3 in women. [4] There is substantial individual variation, [ 4 ] with the standard reference range for men being 1,180–1,620 g (2.60–3.57 lb) [ 5 ] and for women ...