See if you can do these tricky addition and subtraction problems.

This Math quiz is called 'Addition and Subtraction 8' and it has been written by teachers to help you if you are studying the subject at elementary school. Playing educational quizzes is an enjoyable way to learn if you are in the 3rd, 4th or 5th grade - aged 8 to 11.

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In this last elementary school Math quiz on addition and subtraction, you are going to get some practice in adding and subtracting decimals.

1. Add the whole numbers first, then add the decimal parts. For example, 1.5 + 3.6 - 2.4 = (1 + 3 - 2) + (0.5 + 0.6 - 0.4) = 2 + 0.7 = 2.7
2. With numbers less than 1,000, add the hundreds first, then the tens and then the units. For example: 120 + 360 + 25 + 8 = (100 + 300) + (20 + 60 + 20) + (5 + 8) = 400 + 100 + 13 = 513

If you don't get 10 out of 10 the first time you play the quiz, don't worry. Try it again until you have a good grasp of this important aspect of Math. Good luck!

1.
678.1 - 345.2 = ?
332.8
332.7
323.9
332.9
678.1 - 345.2 = (600 - 300) + (70 - 40) + (8 - 5) + (0.1 - 0.2) = 300 + 30 + 3 - 0.1 = 333 - 0.1 = 332.9: Note: with negative numbers, the negative sign is kept with each part of the number, e.g. - 678.6 is written as -600, -70, -8, and -0.6
2.
128.7 + 450.3 - 15.2 + 200 = ?
763.9
763.7
763.8
763.6
128.7 + 450.3 - 15.2 + 200 = (100 + 400 + 200) + (20 + 50 - 10) + (8 - 5) + (0.7 + 0.3 - 0.2) = 700 + 60 + 3 + 0.8 = 763.8
3.
69.9 - 40.6 + 123.4 = ?
152.8
152.6
152.7
152.5
69.9 - 40.6 + 123.4 = (100) + (60 + 20 - 40) + (9 + 3) + (0.9 + 0.4 - 0.6) = 100 + 40 + 12 + 0.7 = 152.7
4.
345.9 + 38.6 - 17.2 = ?
367.3
376.3
367.4
365.3
345.9 + 38.6 - 17.2 = (300) + (40 + 30 - 10) + (5 + 8 - 7) + (0.9 + 0.6 - 0.2) = 300 + 60 + 6 + 1.3 = 367.3
5.
120.3 + 23.4 + 8.6 = ?
152.4
150.2
151.3
152.3
Add the whole numbers first, then add the decimal parts. 120.3 + 23.4 + 8.6 = (100) + (20 + 20) + (3 + 8) + (0.3 + 0.4 + 0.6) = 100 + 40 + 11 + 1.3 = 152.3
6.
200 + 158.3 + 28.9 = ?
378.2
387.2
387.1
387.0
200 + 158.3 + 28.9 = (200 + 100) + (50 + 20) + (8 + 8) + (0.3 + 0.9) = 300 + 70 + 16 + 1.2 = 387.2
7.
23.5 - 14.9 + 146.2 = ?
145.8
154.8
154.7
154.6
23.5 - 14.9 + 146.2 = (100) + (20 + 40 - 10) + (3 + 6 - 4) + (0.5 + 0.2 - 0.9) = 100 + 50 + 5 - 0.2 = 154.8
8.
8.8 - 6.4 - 8.8 + 19.6 = ?
13.2
31.2
13.1
13.0
8.8 - 6.4 - 8.8 + 19.6 = (10) + (9 - 6) + (0.6 - 0.4) = 10 + 3 + 0.2 = 13.2: don't waste time writing numbers that cancel each other out, e.g. 8.8 - 8.8 = 0
9.
2.3 + 5.6 + 12.3 = ?
19.1
20.1
20.2
20.3
Add the whole numbers first, then add the decimal parts. 2.3 + 5.6 + 12. 3 = (10) + (2 + 5 + 2) + (0.3 + 0.6 + 0.3) = 10 + 9 + 1.2 = 20.2
10.
0.8 + 0.2 + 0.7 = ?
1.5
1.2
0.7
1.7
0.8 + 0.2 + 0.7 = (0.8 + 0.2) + 0.7 = 1 + 0.7 = 1.7. Be on the LOOKOUT for decimals that sum to 1
Author:  Frank Evans