Rounding
Round 843 to the nearest ten
840
Add mentally: 136+342
478
Subtract mentally: 75-15
60
Round to the nearest ten to add: 647+121
650+120=770
540-340=200
Round 695 to the nearest ten
700
Add mentally: 276+122
398
Subtract mentally: 87-22
65
Round to the nearest hundred to add: 244+398
200+400=600
Round to the nearest hundred to subtract: 379-86
400-100=300
Round 127 to the nearest ten
130
Add mentally: 538+361
899
Subtract mentally: 124-54
70
Use compatible numbers to add: 103+74
100+75=175
Use compatible numbers to subtract: 344-133
350-130=220
Round 955 to the nearest hundred
1,000
Add mentally: 368+125
493
Subtract mentally: 348-123
225
Elsie earned $27 last week. She earned another $42 this week. About how much money does Elsie have all together?
$30+$40=$70
There are 687 pages in Mary's book. So far, she has read 342 pages. About how many pages does she have left to read?
690-240=450
Round 849 to the nearest hundred
800
Add mentally: 843+142
985
Subtract mentally: 649-224
(add 1 to both: 650-225) 425
Natalie read 23 pages of her book yesterday after school. Today, she read 36 pages of her book. About how many pages has Natalie read?
20+40=60
Anna is making cookies for the school fundraiser. She wants to make 417 cookies total. So far, she has 256 cookies. About how many more cookies does Anna have to make?
420-260=160