The picture shows 7 × 11 × 13 + 13: a 7 by 11 block of squares, each worth 13, plus one more square worth 13 (orange). Why is 7 × 11 × 13 + 13 a composite number?

Question

Accepted Answer

It equals 13 × 78, so 13 is a factor other than 1 and itself. There are 7 × 11 + 1 = 78 squares of 13, so 7 × 11 × 13 + 13 = 13(77 + 1) = 13 × 78 = 1014. It has the factor 13 besides 1 and itself, so it is composite (77 forgets the orange square).

The picture shows $7 \times 11 \times 13 + 13$ : a 7 by 11 block of squares, each worth 13, plus one more square worth 13 (orange). Why is $7 \times 11 \times 13 + 13$ a composite number?

Step-by-Step Solution

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More Class 10 Fundamental Theorem of Arithmetic practice

The picture shows 7×11×13+13: a 7 by 11 block of squares, each worth 13, plus one more square worth 13 (orange). Why is 7×11×13+13 a composite number?

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 Fundamental Theorem of Arithmetic practice

The picture shows $7 \times 11 \times 13 + 13$ : a 7 by 11 block of squares, each worth 13, plus one more square worth 13 (orange). Why is $7 \times 11 \times 13 + 13$ a composite number?