Terry, 4th grade Three is the first number of a pair, and 8 is the second. a. If 50 is the first number, what is the second number? b. If 200 is the first number, what is the second number? c. If 89 is the second number, what is the first number? d. If a number n is the first number, what is the second number? 3-8 4-11 5-14 6-17 ____ ____ ____ 10-29 ____ ____ ____ Hi Terry, If you look at the string of second numbers, 8, 11, 14, 17 you can see that they are going up by 3 each time. 8, 8 + 3 = 11, 11 + 3 = 14, 14 + 3 = 17 Check the next 4 pairs that have first numbers 7, 8, 9 and 10 to make sure that the "add 3" procedure gives the pair 10-29. Now that you see that "add 3" is the procedure, look again at the pairs. Notice that in each case the second number is almost 3 times the first number. In fact each second number is one less than 3 times the first number. 8 is 1 less than 3 times 3 11 is 1 less than 3 times 4 14 is 1 less than 3 times 5 17 is 1 less than 3 times 6 Can you finish the problem now? Penny Go to Math Central