Final answer:
To solve 28 + 13 + 12 mentally, pair numbers to reach a round sum, such as 28 + 12 = 40, then add 13 to reach 53, or add tens first and ones after, both resulting in 53.
Step-by-step explanation:
To solve the math problem 28 + 13 + 12 using mental maths, we can employ various strategies. One strategy is to find numbers that are easy to add together. Recognize that 12 and 28 can be paired to make 40, which is a round number, and then add the remaining 13 to get 53. Another approach could be to add the tens first.
You see that there's two 10s in 28, one 10 in 13, and one 10 in 12, which sums up to 40, and then add the ones place: 8 + 3 + 2 equals 13.
Adding both gives us 53 as well. Mental maths often involves finding ways to simplify numbers or group them into manageable sums.