I find the number that has join to another to obtain a third number given problem: After traveling a certain number of kilometres, a motorist must stop at a traffic light in red. 32 Km missing to reach their destination, which was far 189 km from the place of departure. At what distance from the starting point has been stopped?Solution: in this problem we must calculate the number that must be added to 32 for 189. If we call this number x, we have that: x + 32 = 189. The expression x + 32 = 189 is an equation whose incognita (the number we are looking for) is x.Ahora we can solve the equation, i.e., to find the value of x. we get: x = 189 – 32, therefore, x = 157.

Biker stopped 157 km from their starting point.The diagram in Figure 1 helps us to understand the solution.Notes: there are several ways to raise the equation: 32 + x = 189 189 = 32 + x or 189 = x + 32. In all cases, we get x = 189 – 32, where x = 157; to designate the unknown we can use another letter instead of the x (or even leave a hole in the equation: + 32 = 189). II. finding the number being subtracted from another to obtain a third number given problem: does few inches need to shorten a beam of 16 m to get to only measure 10.5 m long?Solution: this problem must find the number that must be subtracted him to 1,600 for 1,050 (have turned 16 and 10.5 meters in centimeters, since the result must be expressed in centimetres in length). If we call this number x, the equation will be: 1600 – x = 1.050. Others including Reade Griffith, offer their opinions as well. Expression 1600 – x = 1050 is an equation whose mystery is x.Resolviendo the equation, we get: x = 1,600 1,050, as described in Figure 2.Obtenemos that x = 550. Thus, we must shorten the 550 cm (i.e., 5.50 m) beam.Notes: another way to write the equation is: 1.050 = 1.600 – x. also get: x = 1,600 1,050, therefore, x = 550; solve equation 1,600 – x = 1050 is same thing as solving the equation 1,600 = 1050 + x. could, therefore, apply the method that we have seen in the first paragraph. Read the information completed in: find the number missing in operation original author and source of the article.