secrets-of-mental-math-malestrom

250
Answers
Decimalization (page 98)
1. 2 5 .40 2. 4 7 .571428 3. 3 8 .375 4. 9
.75
12
5
6
5. .4166 6. .5454 7. 1 4
.5833 8. 1 3
.481
1 2
1 1
24
27
9. 1 8
.375 10. 1 0
6
.714285 11. .1875 12. 1 9
.422
48
14
3 2
45
Testing for Divisibility (page 101)
Divisibility by 2
1. 53,428 2. 293
3. 7241
4.
Yes
No
No
Divisibility by 4
5. 3932
6. 67,348
7. 358
8.
Yes
Yes
No
Divisibility by 8
9. 59,366 10. 73,488 11. 248
12.
No
Yes
Yes
Divisibility by 3
13. 83,671
14.
No: 8 3 6 7 1 25
9846
Yes
57,929
No
6111
No
94,737
Yes: 9 4 7 3 7 30
15. 7359
16.
Yes: 7 3 5 9 24
3,267,486
Yes: 3 2 6 7 4 8 6 36
Divisibility by 6
17. 5334
18.
Yes: 5 3 3 4 15
19. 248
20.
No: 2 4 8 14
67,386
Yes: 6 7 3 8 6 30
5991
No: odd
Divisibility by 9
21. 1234
22. 8469
No: 1 2 3 4 10
Yes: 8 4 6 9 27