1 .10 times 10: formula: head joint, tail to tail, tail to tail. For example: 12× 14=? Solution:/kloc-0 /×1=12+4 = 62× 4 = 812×14 =168 Note: Numbers are multiplied. If two digits are not enough, please use 0.

2. The heads are the same and the tails are complementary (the sum of the tails is equal to 10): Formula: after a head is added with 1, the head is multiplied by the head and the tail is multiplied by the tail. For example: 23×27=? Solution: 2+1= 32× 3 = 63× 7 = 2123× 27 = 621Note: Multiply the digits. If there are not enough digits, use 0 to fill the space.

3. The first multiplier is complementary, and the other multiplier has the same number: formula: after a head is added with 1, the head is multiplied by the head and the tail is multiplied by the tail. For example: 37×44=? Solution: 3+1= 44× 4 =167× 4 = 28 37× 44 =1628 Note: Number multiplication. If two digits are not enough, please use 0.

4. Dozens of eleven times dozens of eleven: formula: head to head, head to head, tail to tail. For example: 2 1×4 1=? Solution: 2× 4 = 8 2+4 = 6/kloc-0 /×1=121× 41= 8 61.

Mathematics [English: Mathematics, derived from the ancient Greek μ θ η μ α (má th ē ma); Often abbreviated as math or maths], it is a discipline that studies concepts such as quantity, structure, change, space and information.

Mathematics is a universal means for human beings to strictly describe the abstract structure and mode of things, and can be applied to any problem in the real world. All mathematical objects are artificially defined in essence. In this sense, mathematics belongs to formal science, not natural science. Different mathematicians and philosophers have a series of views on the exact scope and definition of mathematics.

Mathematics plays an irreplaceable role in the development of human history and social life, and it is also an indispensable basic tool for studying and studying modern science and technology.