Meena writes two-digit numbers in which the tens digit is exactly double the units digit, like 21 (2 = 2x1) and 42 (4 = 2x2). How many such two-digit numbers are there in all?

Question

Accepted Answer

4. Units digit u with tens 2u being a single digit and tens not 0: u=1->21, u=2->42, u=3->63, u=4->84. u=0 gives 00 (not two-digit). So 4 numbers.

Meena writes two-digit numbers in which the tens digit is exactly double the units digit, like 21 $(2 = 2 \times 1)$ and 42 $(4 = 2 \times 2)$ .
How many such two-digit numbers are there in all?

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More Class 6 Patterns in Whole Numbers practice

Meena writes two-digit numbers in which the tens digit is exactly double the units digit, like 21 (2=2×1) and 42 (4=2×2).How many such two-digit numbers are there in all?

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 6 Patterns in Whole Numbers practice

Meena writes two-digit numbers in which the tens digit is exactly double the units digit, like 21 $(2 = 2 \times 1)$ and 42 $(4 = 2 \times 2)$ .
How many such two-digit numbers are there in all?