Partial Sum Method
320 + 241 =
500 + 60 + 1 = 561
98 + 45 =
100 + 43 = 143
234 + 152 =
386
2.3 + 1.4 =
3.7
A library has 125 fiction books and 143 nonfiction books.
How many books are there altogether?
268 books
125 + 143 = 268
543 + 236 =
700 + 70 + 9 =
299 + 176 =
300 + 175 = 475
468 + 257 =
725
4.25 + 3.16 =
7.41
A school collected 378 cans on Monday and 456 cans on Tuesday.
How many cans were collected altogether?
834 cans
378 + 456 = 834
822 + 164 =
900 + 80 + 6 = 986
497 + 268
500 + 265 = 765
1,785 + 2,649 =
4,434
5.478 + 2.356 =
7.834
Maya walked 2.45 km on Saturday and 3.375 km on Sunday.
How far did she walk altogether?
5.825 km
2.450 + 3.375 = 5.825
375 + 517 =
800 + 80 + 12 = 892
1,998 + 756 =
2,000 + 754 = 2,754
6,758 + 4,896 =
11,654
8.65 + 3.789 =
12.439
A school raised $1,478.65 at a bake sale and $2,896.75 at a basketball fundraiser.
How much money did the school raise altogether?
$4,375.40
1,478.65 + 2,896.75 = 4,375.40
667 + 253 =
800 + 110 + 10 = 920
A student changes 4,995 + 2,687 into 5,000 + 2,687. Explain the mistake and solve correctly using compensation.
The student added 5 to the first number but forgot to subtract 5 from the second number.
5,000 + 2,682 = 7,682
Use the traditional stacking method to solve:
48,769 + 37,584 + 6,895
93,248
A student says:
6.875 + 4.968 = 10.843
Is the student correct? Explain the mistake and find the correct answer.
11.843
A hiking group travelled:
3.875 km in the morning
4.96 km in the afternoon
2.785 km in the evening
Their goal was to travel 12 km.
Did they reach their goal? How much farther must they travel, or how far did they exceed it?
No, they did not reach their goal.
3.875 + 4.960 + 2.785 = 11.620 km
12 − 11.620 = 0.380 km
They need to travel another 0.380 km (380 metres) to reach their goal.