Question

multiply by 2s
count by 2s.
2→4→6→8→10→12→14→16→18→20
complete the input/output table.
input 2 6 8 3 7 10 5 1 0 4
multiply by 2
find the number missing from each fact family.
what fact is shown by the illustration
3 □ 8
7 □ 2×9
20 □ 2×10
6 □ 2×5
4 × 2 = 8

Explanation:

Step1: Complete the input - output table

Multiply each input number by 2.
$2\times2 = 4$, $6\times2=12$, $8\times2 = 16$, $3\times2=6$, $7\times2 = 14$, $10\times2=20$, $5\times2 = 10$, $1\times2=2$, $0\times2 = 0$, $4\times2=8$.
The completed output row is: 4, 12, 16, 6, 14, 20, 10, 2, 0, 8.

Step2: Find the missing numbers in the triangles

For the first triangle with 7 and 12, assume the operation is addition, the missing number is $12 - 7=5$.
For the second triangle with 5 and 2, assume the operation is addition, the missing number is $5 + 2=7$.
For the third triangle with 12 and 6, assume the operation is division (since $12\div6 = 2$), the missing number is 2.

Step3: Compare the numbers

$3<8$; $2\times9 = 18$, so $7<2\times9$; $2\times10=20$, so $20 = 2\times10$; $2\times5 = 10$, so $6<2\times5$.

Answer:

Input - output table output row: 4, 12, 16, 6, 14, 20, 10, 2, 0, 8
First triangle missing number: 5
Second triangle missing number: 7
Third triangle missing number: 2
Comparisons: $3<8$, $7<2\times9$, $20 = 2\times10$, $6<2\times5$