Final answer:
In front-end estimation, the sum of 149.23 and 152.78 is approximated by considering only the most significant digits (the hundreds place), resulting in 300. The smaller decimals are disregarded for a quick estimation of the total.
Step-by-step explanation:
To estimate 149.23 + 152.78 using front-end estimation, first add the whole number parts: 149 + 152 = 301. Since front-end estimation focuses on the most significant digits, the decimals are not accounted for in detail. However, if we include the next significant digit after the decimal for a slightly more accurate estimate, we observe that .2 and .7 roughly add up to 1, bringing our estimate to roughly 302.
Therefore, a front-end estimation of 149.23 + 152.78 would give us an approximate sum of 302.