Test 2. Highest common factor

Before proceeding to the solution of examples and problems be sure to read the theoretical part of the lesson 

Highest common factor

 1. Find the Highest Common Factor of

15 and 35

 а)  7;      b)  3;     

 c)  5;      d)  1.

 2. Find the Highest Common Factor of

15 and 40

 а)  10;      b)  5;     

 c)  3;        d)  8.

 3. Find the Highest Common Factor of

12 and 20

 а)  12;      b)  3;     

 c)  5;        d)  4.

 4. Find the Highest Common Factor of

16 and 40

 а)  8;      b)  4;     

 c)  2;      d)  10.

 5. Find the Highest Common Factor of

11 and 13

 а)  11;      b)  13;     

 c)  1;        d)  7.

 6. Find the Highest Common Factor of

16 and 48

 а)  8;      b)  4;     

 c)  2;      d)  16.

 7. Copy the numbers below and put a cirle round all the common factors for each pair of numbers.

180 = 2 × 2 × 3 × 3 × 5

120 = 2 × 2 × 2 × 3 × 5

Write down the HCF of 180 and 120.

 а)  20;      b)  60;     

 c)  30;      d)  10.

 8. Copy the numbers below and put a cirle round all the common factors for each pair of numbers.

720 = 2 × 2 × 2 × 2 × 3 × 3 × 5

600 = 2 × 2 × 2 × 3 × 5 × 5

Write down the HCF of 720 and 600.

 а)  120;      b)  10;     

 c)  30;        d)  60.

 9. Copy the numbers below and put a cirle round all the common factors for each pair of numbers.

3850 = 2 × 5 × 5 × 7 × 11

140 = 2 × 2 × 5 × 7

Write down the HCF of 3850 and 140.

 а)  35;        b)  70;     

 c)  140;      d)  5.

10. Find the HCF of

4,  6 and 12

 а)  4;      b)  6;     

 c)  2;      d)  1.

11. Find the HCF of

10,  20 and 45

 а)  3;       b)  1;     

 c)  10;      d)  5.

12. Find the HCF of

24,  48 and 60

 а)  24;      b)  6;     

 c)  12;      d)  3.