Estimating
Estimate the sum by rounding to the nearest hundred.
178 + 221 =
200 + 200 = 400
4 + 354 =
358
678 - 451 =
227
Nick walked 12 feet on Monday. Then he walked 72 more feet on Tuesday. How far did Nick walk?
84 feet
3 feet + 2 inches =6 feet
false
Estimate the sum by rounding to the nearest ten.
65 + 113 =
70 + 110 = 180
36+ 42 =
78
640 - 212 =
428
Mrs. Yeniffer had 537 eggs. She sold 292 eggs to a bakery. How many eggs did Yeniffer have left?
245 eggs
The answer to a subtraction problem is called a difference.
True
Estimate the sum by rounding to the nearest ten.
684 + 159 =
680 + 160 = 840
83 + 595 =
678
748 - 469 =
279
Brandon spent $157 on a video game. He now has $129 in his bank account. How much money did he have to start with?
$286
An estimate is close to the real number.
true
Estimate the difference by rounding to the nearest ten.
367 - 145 =
370 - 150 = 220
146 + 100=
246
100-50
50
Janelle and Jarred bought 431 cards. They gave 105 cards to their friend. Then they bought 237 more cards. How many cards do they have now?
563 cards
Subtraction
Estimate the difference by rounding to the nearest ten.
713 - 469 =
710 - 470 = 240
679 + 227 =
906
812 - 317 =
495
Ms. Whelan's sniffling students use 188 tissues on Monday, 356 tissues on Tuesday, and 275 tissues on Wednesday. Ms. Whelan had 1,000 tissues at the beginning of the week. How many tissues are left?
188 + 356 + 275 = 819
1,000 - 819 = 181
Two operations that undo each other, such as addition and subtraction.
Inverse Operations