18APR21SUN
What is the sum of 1, 2, 3, … up to 10?
10 terms
5 pairs
each pair 11
Sum of series = 5*11 = 55
What is the sum of 1, 2, 3, … up to 20?
20 terms
10 pairs
each pair 21
Sum of series = 10*21 = 210
What is the sum of 1, 2, 3, … up to 30?
30 terms
15 pairs
each pair 31
Sum of series = 15*31 = 465
What is the sum of 1, 2, 3, … up to 40?
40 terms
20 pairs
each pair 41
Sum of series = 20*41 = 820
What is the sum of 1, 2, 3, … up to 50?
50 terms
25 pairs
each pair 51
Sum of series = 25*51 = 1275
What is the sum of 1, 2, 3, … up to 60?
60 terms
30 pairs
each pair 61
Sum of series = 30*61 = 1830
What is the sum of 1, 2, 3, … up to 70?
70 terms
35 pairs
each pair 71
Sum of series = 35*71 = 2485
What is the sum of 1, 2, 3, … up to 80?
80 terms
40 pairs
each pair 81
Sum of series = 40*81 = 3240
What is the sum of 1, 2, 3, … up to 90?
90 terms
45 pairs
each pair 91
Sum of series = 45*91 = 4095
What is the sum of 1, 2, 3, … up to 100?
100 terms
50 pairs
each pair 101
Sum of series = 50*101 = 5050
What two numbers will you multiply to find the sum of 1, 2, 3, … up to 1000?
500 and 1001
What two numbers will you multiply to find the sum of 1, 2, 3, … up to 200?
100 and 201
What two numbers will you multiply to find the sum of 1, 2, 3, … up to 199?
half of 199 and 200, or, 199 and half of 200
What is the sum of the series 1, 3, 5, 7, 9, 11, 13, 15, 17, 19?
10 terms [{(19 - 1) / 2} + 1]
5 pairs
each pair 20
Sum = 5*20 = 100
What is the sum of the series 2, 4, 6, 8, 10, 12, 14, 16, 18, 20?
10 terms
5 pairs
each pair 22
Sum = 5*22 = 110
What is the sum of the series 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, … up to 121?
61 terms [{(121 - 1) / 2} + 1]
each pair 122
Sum = 61 * half of 122 = 61*61 = 3721
What is the sum of the series 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, … up to 140?
70 terms [{(140 - 2) / 2} + 1], 35 pairs, each 142
Sum = 35*142 = 4970
What is the sum of 2, 5, 8, 11, … up to 65?
22 terms [{(65 - 2) / 3} + 1], 11 pairs, each 67
Sum = 11*67 = 737
What is the sum of 3, 7, 11, 15, … up to 115?
29 terms [{(115 - 3) / 4} + 1], each pair 118
Sum = half of 29 * 118 = 29 * half of 118 = 29*59 = 1711
Comments
Post a Comment