Prudente, Virgilio Y. , author ,
25 math short cuts / Virgilio Y. Prudente. --
Addition by creating zeroes All from 9 and the last from 10 subtraction Subtraction without borrowing Multiplying by 2 Doubling and halving together Multiplying by 9 Diving by 5, 50, 0.5 etc. Multiplying by 5, 50, 5%, etc. Dividing by 9 Dividing by 4 and 8 Multiplying by 25, 250, and 125 Dividing by 25, 250, and 125 Squaring numbers ending in 5 Multiplying complementary numbers Base multiplication : teens and other Base multiplication : numbers below the base Base multiplication : one number above and once number below the base Squaring numbers near 50 Multiplying numbers with the same units Multiplying numbers ending in 5 Multiplying number when their average is a multiple of 10 Squaring any number
Ready-reckoners
513.9
25 math short cuts / Virgilio Y. Prudente. --
Addition by creating zeroes All from 9 and the last from 10 subtraction Subtraction without borrowing Multiplying by 2 Doubling and halving together Multiplying by 9 Diving by 5, 50, 0.5 etc. Multiplying by 5, 50, 5%, etc. Dividing by 9 Dividing by 4 and 8 Multiplying by 25, 250, and 125 Dividing by 25, 250, and 125 Squaring numbers ending in 5 Multiplying complementary numbers Base multiplication : teens and other Base multiplication : numbers below the base Base multiplication : one number above and once number below the base Squaring numbers near 50 Multiplying numbers with the same units Multiplying numbers ending in 5 Multiplying number when their average is a multiple of 10 Squaring any number
Ready-reckoners
513.9