Estimating Differences
Estimate the difference to the nearest hundred.
789 - 321 =
500
Find n.
n-3=12
n=15
413 - 208 =
205
604 - 127=
477
Write a number sentence is in the same fact family with 2+5=7
5+2=7
or
7-2=5
or
7-5=2
Round to the nearest 10 to estimate the difference.
843-559 =
280
Write a number sentence with n as your variable.
Use the numbers 18 and 6.
Solve for n.
(Hint: there are 3 different answers)
18 - 6 = n n=12
n- 6 = 18 n=24
18-n = 6 n=12
Sloane has a necklace that is 195 years old. Priya has a necklace that is 76 years old. How much older is Sloane's necklace than Priya's?
119 years
Harmony auditorium had 300 chairs. The teachers are sitting in 35 of the chairs. How many chairs are left for the parents?
265 chairs
Claire has 13 bows. She shared some bows with her friends at cheerleading, so now she only as 7. Write a number sentence with x to solve how many bows she gave away.
13-x=7
or
13-7=x
Cora kicked the soccer ball 126 times in practice. Syrus kicked the soccer ball 561 times in practice. ABOUT how many more times did Syrus kick the ball than Cora? Round to the nearest ten.
430 times
Find n. Explain how you know n is reasonable.
n - 4 = 12
n = 16
To find if n is reasonable you should put your value into the number sentence to see if your sentence is true. I checked my work and 16 - 4 = 12, so my answer is reasonable.
Solve the difference for 761 - 496 =
Do you need to regroup? How do you know?
265
Yes. You need to regroup because if you stack the numbers there is more on the floor in both the ones and tens.
Meredith completed the problem 800-753. She said her answer is 57. Is she correct? If no, what did she do wrong?
Meredith is not correct because when we subtract 800-753 the answer should be 47. Meredith did not regroup in the tens place to make her 10 a 9.
Jacob completed 425 math problems on Prodigy. He wants to complete 502. How many more problems does he need to complete? Write a number sentence with x and solve.
425+ x= 502
or
502-425= x
x=77