7 and 21
They can be: 73+7 = 80
How about 7 times 7 = 49 as one example
-175
17
7 and 21
List numbers that multiply to make 28 and find their sums. Since negative times a negative is positive, list the negatives. -1, -28 = -29 -2, -14 = -15 -4, -7 = -11 Aha! -4 and -7 multiply to make 28 and add to -11; therefore, -4 and -7 are the two numbers.
They can be: 73+7 = 80
127
How about 7 times 7 = 49 as one example
-7
47
Yes just add them up.
7 and 13
-175
You can, if you have a square with side 5 you can multiply 5*5=25 or you can add 5+5+5+5+5=25 If you want to do this just take one of the numbers and add it to itself the other numbers times. so if you have 7*8 you add 7 to itself 8 times, so add 8 7's 7+7+7+7+7+7+7+7=56 or add 7 8's 8+8+8+8+8+8+8=56 Multiplying is much easier.
They are: 2*5*7*7 = 490